FINAL Record of Decision
January 2016 Revision 03
Fort Riley Sherman Heights Small Arms Range Impact Slope Junction City, Kansas
Military Munitions Response Program U.S. Army Corps of Engineers, Omaha District Contract W9128F-09-D-0059, Task Order 0009
FINAL
CONTRACT W9128F-09-D-0059 TASK ORDER 0009
MMRP RECORD OF DECISION
FORT RILEY SHERMAN HEIGHTS SMALL ARMS RANGE IMPACT SLOPE JUNCTION CITY, KANSAS
Prepared for:
U.S. ARMY Fort Riley
Prepared by:
U.S. ARMY CORPS OF ENGINEERS Omaha District
January 2016 Revision 03
Record of Decision Sherman Heights Small Arms Range Impact Slope Fort Riley, Kansas
Table of Contents 1.0 DECLARATION ...... 1-1 1.1 Site Name and Location ...... 1-1 1.2 Statement of Basis and Purpose ...... 1-1 1.3 Assessment of Site ...... 1-1 1.4 Description of Selected Remedy ...... 1-1 1.5 Statutory Determinations ...... 1-2 1.5.1 Part 1: Statutory Requirements ...... 1-2 1.5.2 Part 2: Statutory Preference for Treatment ...... 1-2 1.5.3 Part 3: Five-Year Review Requirement ...... 1-2 1.6 ROD Data Certification Checklist ...... 1-2 1.7 Authorizing Signatures ...... 1-3 2.0 DECISION SUMMARY ...... 2-1 2.1 Site Name, Location, and Brief Description ...... 2-1 2.2 Site History and Enforcement Activities ...... 2-1 2.3 Community Participation ...... 2-4 2.4 Scope and Role of MRS or Response Action ...... 2-6 2.5 Site Characteristics ...... 2-6 2.5.1 Topography ...... 2-6 2.5.2 Climate ...... 2-6 2.5.3 Geology and Hydrology ...... 2-7 2.5.4 Hydrogeology ...... 2-7 2.5.5 Hydrology ...... 2-8 2.5.6 Vegetation ...... 2-8 2.5.7 Ecology ...... 2-9 2.5.8 Nature and Extent of Contamination ...... 2-9 2.6 Current and Potential Future Land Use and Resource Uses ...... 2-13 2.6.1 Conceptual Site Model ...... 2-13 2.7 Summary of Site Risks ...... 2-16 2.7.1 Summary of the Human Health Risk Assessment ...... 2-16 2.7.2 Summary of the Ecological Risk Assessment ...... 2-20 2.7.3 Basis for Taking Action ...... 2-24 2.8 Remedial Action Objectives ...... 2-24 2.9 Description of Alternatives ...... 2-25 2.9.1 Alternative 1: No Action ...... 2-26 2.9.2 Alternative 2: LUCs ...... 2-26 2.9.3 Alternative 3: Excavation and Off-Site Disposal ...... 2-27 2.9.4 Alternative 4: Soil Cover ...... 2-28 2.10 Comparative Analysis of Alternatives ...... 2-28 2.10.1 Overall Protection of Human Health and the Environment ...... 2-29 2.10.2 Compliance with Applicable or Relevant and Appropriate Requirements ...... 2-30 2.10.3 Long-Term Effectiveness and Permanence ...... 2-30 2.10.4 Reduction of Toxicity, Mobility, or Volume Through Treatment ...... 2-31 2.10.5 Short-Term Effectiveness ...... 2-31 2.10.6 Implementability ...... 2-31 2.10.7 Cost ...... 2-32
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2.10.8 Regulatory Acceptance ...... 2-33 2.10.9 Community Acceptance ...... 2-33 2.11 Principal Threat Wastes ...... 2-34 2.12 Selected Remedy ...... 2-34 2.12.1 Summary of the Rationale for the Selected Remedy ...... 2-34 2.12.2 Summary of Estimated Remedy Costs ...... 2-34 2.12.3 Expected Outcomes of Selected Remedy ...... 2-35 2.13 Statutory Determinations ...... 2-35 2.13.1 Protection of Human Health and the Environment ...... 2-35 2.13.2 Compliance with ARARs ...... 2-35 2.13.3 Cost Effectiveness ...... 2-35 2.13.4 Utilization of Permanent Solutions and Alternative Treatment Technologies to the Maximum Extent Practicable ...... 2-36 2.13.5 Preference for Treatment as a Principal Element ...... 2-36 2.13.6 Five-Year Review Requirements ...... 2-36 2.14 Documentation of Significant Changes ...... 2-36 3.0 RESPONSIVENESS SUMMARY ...... 3-1 3.1 Stakeholder Comments and Lead Agency Responses ...... 3-1 3.2 Community Participation ...... 3-1 3.1 Summary of Comments Received during the Public Comment Period and Agency Responses ...... 3-1 3.1.1 Comments Received During the Public Meeting ...... 3-1 3.1.2 Written Comments Received During the Comment Period ...... 3-2 3.3 Technical and Legal Issues ...... 3-2 4.0 REFERENCES ...... 4-1
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List of Tables Table 1-1 ROD Data Certification Checklist ...... 1-2 Table 2-1 MEC Summary ...... 2-3 Table 2-2 Public Notification of Document Availability ...... 2-5 Table 2-3 Public Comment Period Requirements ...... 2-5 Table 2-4 Previous MRS Characterization Activities Summary ...... 2-9 Table 2-5 Lead Concentrations Compared to Human Health Risk-Based Screening Levels ...... 2-18 Table 2-6 Screening of Chemicals of Potential Ecological Concern ...... 2-20 Table 2-7 COPEC Risk Characterization for Various Soil Concentrations ...... 2-22 Table 2-8 Basis for Taking Action ...... 2-24 Table 2-9 Summary of Remedial Alternatives Evaluated for the MRS ...... 2-25 Table 2-10 Summary of Comparative Analysis of Alternatives...... 2-29 Table 2-11 Summary of Site-Specific ARARs ...... 2-30 Table 2-12 Cost Estimate Summary for the Selected Remedy ...... 2-33
List of Figures Figure 2-1 Project Site Location ...... 2-2 Figure 2-2 Timeline of MRS History, Investigations, and Actions ...... 2-4 Figure 2-3 MEC/MD Locations Reported from Previous Investigations ...... 2-11 Figure 2-4 RI MC Sample Locations and Results ...... 2-12 Figure 2-5 MEC Exposure Conceptual Site Model ...... 2-14 Figure 2-6 MC Exposure Conceptual Site Model – Human Receptors ...... 2-15
List of Attachments Attachment 1 – USEPA and KDHE Letters of Concurrence Attachment 2 – Public Notice Proofs Attachment 3 – Transcripts from Public Meeting Attachment 4 – Responses to Comments
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Acronyms and Abbreviations
% ...... percent HHRA ...... human health risk °F ...... degrees Fahrenheit assessment µg/dL ...... micrograms per deciliter HQ ...... hazard quotient ABLES ...... Adult Blood Level ID ...... identification Epidemiology and IEUBK ...... Integrated Exposure-Uptake Surveillance Biokinetic Model ALM ...... adult lead model INRMP ...... Integrated Natural Resources ARAR ...... applicable or relevant and Management Plan appropriate requirements IS ...... incremental sampling Army ...... United States Army KDHE ...... Kansas Department of ASL ...... above screening level Health and Environment Bay West ...... Bay West LLC lbs ...... pounds bgs ...... below ground surface LOAEL ...... lowest observed adverse BSL ...... below screening level effect level CDC ...... Centers for Disease Control LUC ...... land use control and Prevention MC ...... munitions constituents CERCLA ...... Comprehensive MCL ...... maximum contaminant level Environmental Response, MD ...... munitions debris Compensation, and Liability MDAS ...... material documented as safe Act of 1980 MEC ...... munitions and explosives of CERCLIS ...... Comprehensive concern Environmental Response, MEC-HA ...... MEC hazard assessment Compensation, and Liability mg/day ...... milligrams per day Information System mg/kg ...... milligrams per kilogram CFR ...... Code of Federal Regulations MMRP ...... Military Munitions Response COC ...... chemical of concern Program COPC ...... chemical of potential concern MRA ...... munitions response area COPEC ...... chemical of potential MRS ...... munitions response site ecological concern msl ...... mean sea level CSM ...... conceptual site model NCP ...... National Oil and Hazardous DERP ...... Defense Environmental Substances Pollution Restoration Program Contingency Plan DGM ...... Digital Geophysical Mapping ND ...... not detected e²M ...... Engineering Environmental NOAEL ...... no observed adverse effect Management, Inc. level Eco-SSL ...... ecological soil screening NPL ...... National Priorities List level O&M ...... operation and maintenance EF ...... exposure frequency OHM ...... OHM Corporation ERA ...... ecological risk assessment OSHA ...... Occupational Safety and ESD ...... Explanation of Significant Health Administration Differences PbB ...... blood lead concentration FS ...... Feasibility Study PP ...... Proposed Plan ft ...... foot/feet PPE ...... personal protective GIS ...... Geographical Information equipment System RAGS ...... Risk Assessment Guidance GSR ...... green sustainable for Superfund remediation RAO ...... remedial action objective RBC ...... risk-based concentration
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RCRA ...... Resource Conservation and SLERA ...... screening level ecological Recovery Act risk assessment RfD ...... non-cancer references dose SU ...... sampling unit RG ...... remediation goal TAL ...... target analyte list RI ...... remedial investigation TO ...... task order ROD ...... Record of Decision TRV ...... toxicity reference value RSL ...... regional screening level U.S...... United States SAR ...... species at risk U.S.C...... United States Code SARA ...... Superfund Amendments and UCL ...... upper confidence limit Reauthorization Act of 1986 USEPA ...... U.S. Environmental SHSAR ...... Sherman Heights Small Protection Agency Arms Range UU/UE ...... unlimited use/unrestricted SI ...... site investigation exposure SINC ...... species in need of XRF ...... X-ray fluorescence conservation
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1.0 DECLARATION
1.1 Site Name and Location This Record of Decision (ROD) presents the selected remedial action for the Sherman Heights Small Arms Range (SHSAR) Impact Slope Munitions Response Site (MRS) at Fort Riley, Comprehensive Environmental Response, Compensation, and Liability Information System (CERCLIS) Identification (ID) #KS6214020756. Fort Riley is located near Junction City in Geary, Riley, and Clay Counties in northeast Kansas.
1.2 Statement of Basis and Purpose This ROD presents the selected remedy for the SHSAR Impact Slope MRS at Fort Riley. The selected remedy was chosen in accordance with the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), as amended by the Superfund Amendments and Reauthorization Act of 1986 (SARA), and to the extent practicable with the National Oil and Hazardous Substances Pollution Contingency Plan (NCP). This decision is based on the Administrative Record file for the SHSAR Impact Slope MRS. This document is issued by the United States Army (Army), the lead agency for MRS activities. The U.S. Environmental Protection Agency (USEPA) is the lead regulatory agency with support from the Kansas Department of Health and Environment (KDHE). The Army has consulted with USEPA and KDHE, and they concur with the selected remedy. Letters of approval from the KDHE and USEPA are provided in Attachment 1.
1.3 Assessment of Site The response action selected in this ROD is necessary to protect human health and the environment from actual or threatened releases of pollutants or contaminants from this MRS. There may be a potential imminent and substantial endangerment to human health or the environment.
1.4 Description of Selected Remedy The selected remedy for the MRS is Alternative 2: Land Use Controls (LUCs; Land Use Requirements). Lead is the primary contaminant at the MRS. Lead is a not a principal threat waste. Therefore, there are no principal threat wastes at the MRS. The major components of the selected remedy are presented below. Public education; Legal restrictions on future land use; Physical access restrictions; and Long-term monitoring/maintenance. LUCs will be required indefinitely or until such a time as it is determined that contamination levels are below the remedial goal of 400 milligrams per kilogram (mg/kg). The LUCs will be documented and further developed in a LUC Plan that will be prepared after approval of this ROD. The SHSAR Impact Slope MRS is one of two MRSs currently being investigated at Fort Riley. The other MRS is being addressed separately and does not impact the decisions made for the SHSAR Impact Slope MRS. The selected remedy is intended to be the final remedy for the MRS and does not impact any other areas at Fort Riley.
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1.5 Statutory Determinations 1.5.1 Part 1: Statutory Requirements The selected remedy for the MRS is protective of human health and the environment, complies with applicable or relevant and appropriate requirements (ARARs), is cost effective, and utilizes permanent solutions to the maximum extent practicable. 1.5.2 Part 2: Statutory Preference for Treatment The selected remedy for the MRS does not satisfy the statutory preference for treatment because it does not permanently and significantly reduce the toxicity or volume of lead in the soils. Removal of lead in soil was not recommended due to the steep slopes present, making excavation of soils difficult. Treatment technologies for lead are not commercially available. Further, migration of lead from the MRS has not occurred and is not anticipated. Any risks can be reliably controlled using LUCs. 1.5.3 Part 3: Five-Year Review Requirement Because this remedy will result in hazardous substances, pollutants, or contaminants remaining at the SHSAR Impact Slope MRS above levels that allow for unlimited use and unrestricted exposure (UU/UE), a statutory review, in accordance with NCP Section 300.430(f)(4)(ii), will be conducted every 5 years after initiation of the remedial action to ensure that the remedy is, or will be, protective of human health and the environment. Recurring reviews will continue to be conducted every 5 years until risk management is no longer required.
1.6 ROD Data Certification Checklist The following information is included in the Decision Summary section of this ROD (Section 2.0) as shown in Table 1-1. Additional details are included in the Administrative Record file for the MRS, maintained at Fort Riley, Kansas, and at the Manhattan Public Library, Manhattan, Kansas. Table 1-1 ROD Data Certification Checklist ROD Data Section Chemicals of concern (COCs) and their respective concentrations Section 2.5.8 Baseline risks represented by the COCs Section 2.7 Cleanup levels and the basis for these levels Section 2.8 Not applicable; no principal How source materials constituting principal threats are addressed threat wastes Current and reasonably anticipated future land use assumptions Section 2.6 Potential land and groundwater use that will be available at the MRS Section 2.12.3 as a result of the selected remedy Estimated capital, annual operation and maintenance (O&M), total present worth costs, discount rate, and the number of years over Section 2.12.2 which the remedy cost estimates are projected Key factor(s) that led to selecting the remedy Section 2.12.1
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Record of Decision Sherman Heights Small Arms Range Impact Slope Fort Riley, Kansas
2.0 DECISION SUMMARY
The decision summary identifies the selected remedy, explains how the remedy fulfills statutory and regulatory requirements, and provides a substantive summary of the Administrative Record file that supports the remedy selection decision. This decision summary provides an overview of the MRS characteristics, alternatives evaluated, and the analysis of those alternatives. It also identifies the selected remedy and explains how the remedy fulfills statutory and regulatory requirements. Although some of the information presented here is similar to that in the declaration, this section discusses the topics in greater detail and provides the rationale for the summary declarations presented in Section 1.5. While this document provides a consolidated summary of information about the MRS and the chosen remedy, including the rationale behind the selection, it is only one part of the Administrative Record file, which contains the full details of MRS characterization, alternatives evaluation, and remedy selection. This ROD has been prepared in accordance with USEPA guidance EPA/540-R-98-031 (USEPA, 1999) and the USEPA Toolkit for Preparing CERCLA Records of Decision (USEPA, 2011a). The ROD is based on the Remedial Investigation/ Feasibility Study (RI/FS; Bay West LLC [Bay West], 2014a).
2.1 Site Name, Location, and Brief Description Fort Riley (CERCLIS ID #KS6214020756) is located in portions of Clay, Geary, and Riley counties in northeast Kansas (Figure 2-1). The Installation encompasses approximately 101,733 acres and lies 10 miles west of Manhattan, 50 miles west of Topeka, 135 miles west of Kansas City, and 130 miles north-northeast of Wichita, Kansas. Fort Riley is located at the confluence of the Smoky Hill and Republican rivers, which combine to form the Kansas River. Portions of the Post are bounded by the cities of Riley, Junction City, and Ogden, Kansas. Approximately 70,926 acres are used for maneuver training. The SHSAR Impact Slope MRS is located on Fort Riley near the southern Post boundary. The SHSAR Impact Slope MRS is approximately 150 to 400 feet (ft) wide by 8,000 ft in length (52.00 acres) and is located between the Colyer Manor military family housing complex and the Sherman Heights highlands (Figure 2-1). The overall cleanup strategy for the property is to protect human health and environmental resources given the current and reasonably anticipated future land uses. The Army is the lead agency for MRS activities, and the USEPA and the KDHE are the support agencies for MRS activities. As the lead agency, the Army will conduct and fund remedial activities and decisions at the MRS.
2.2 Site History and Enforcement Activities The SHSAR Impact Slope MRS is part of the SHSAR Munitions Response Area (MRA). A 2005 Historical Records Review indicated that the SHSAR MRA was used for a variety of munitions- related training activities (including anti-aircraft and anti-tank ranges) dating back to the 1880s (Engineering Environmental Management [e²M], 2005) in addition to small arms training. As a result of stakeholder discussions, the SHSAR MRA was reconfigured. The SHSAR MRA was expanded and split into two MRSs: the SHSAR Firing Points MRS (FTRI-001-R-01) and the SHSAR Impact Slope MRS (FTRI-001-R-02).
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Figure 2-1 Project Site Location
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The SHSAR Firing Points MRS (FTRI-001-R-01) was investigated and no munitions and explosives of concern (MEC) or munitions debris (MD) were identified within the revised boundaries. Soil samples collected did not exceed the KDHE Bureau of Environmental Remediation Tier 2 Standards or USEPA Regional Screening Levels (RSLs). Accordingly, the MRS was recommended for no further action at the conclusion of the Site Investigation (SI; e2M, 2006). The SHSAR Impact Slope MRS was reportedly operational in the 1880s. Munitions-related activities were discontinued in 1946 except for a small arms range that remained in use until the late 1980s. The SHSAR Impact Slope MRS was used primarily as a practice firing range for small arms and machine guns. However, the SHSAR Impact Slope MRS also included a cluster of ranges for pistols, anti-aircraft, anti-tank, machine gun, and mortars along Sherman Heights. Firing was to the north toward Sherman Heights, which rises in elevation by approximately 100 ft. The ranges covered approximately 198.93 acres and overlapped to form an arc-shaped area within the southern boundary of the installation and north of the Republican River. Much of the area was developed into the Colyer Manor Family residential housing complex. There are also recreational fields east of the housing complex. Between 1994 and 2011, three studies were performed at the SHSAR Impact Slope MRS that included field investigation for MEC and/or sample collection for environmental characterization. The studies and associated reports follow: 1994 X-Ray Fluorescence (XRF) Survey and Confirmatory Sampling (OHM Corporation [OHM], 1994); 2005 Site Inspection (e2M, 2006); and 2010-2011 RI/FS (Bay West, 2014a). Following the 1994 soil sampling, a lead removal action was performed at the Colyer Manor housing district. Approximately 1,500 cubic yards of soil with a highest measured concentration of 1,700 mg/kg were removed to remediate lead levels to below the USEPA Residential RSL/KDHE Tier 2 Standard of 400 mg/kg. The majority of this soil was south of the SHSAR Impact Slope MRS boundary. In addition, as part of the RI, a full-coverage survey for MEC was completed. This included removal of items from the surface and subsurface soils and utilized the same methods as those employed for a removal action. The net effect of the investigation was a removal action; therefore, a no further action determination for MEC was warranted. Three MEC items were recovered during the RI/FS intrusive investigation. These items are summarized on Table 2-1. Table 2-1 MEC Summary Depth Detection DGM Nomenclature Quantity Recovered Grid Method Target ID (ft) Mk 3 Mod 7, 3-inch common DGM 1 2.0 L58 L58_0002 projectile fuzed 3-inch Hotchkiss projectile, DGM 1 0.5 O49 049_0008 fuzed M6 Rocket, 2.36-inch, Anti- Analog 1 0.5 Q50 N/A tank
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In addition, 597 pounds of munitions debris (MD) were recovered. A list of the types of MD recovered follows: 4" Stokes Mortar (Practice) Expended Fragments from various projectiles Signal, Ground, Expended (Handheld type also known as Slap Flare, e.g. M125, M126, M128) Signal, Ground, Expended (Rifle launched, E.g. M19) M1907m Combination Fuze, Expended M201a1 Fuze, Grenade, Smoke, Expended M23 Grenade, Rifle, Smoke, Expended M28 Primer, Projectile, Expended M30, Grenade, Hand, Practice, Expended M6 2.36-Inch Rocket Motor, Expended M6 2.36-Inch Rocket Fuze Expended Mk I 75mm Shell, Shrapnel, Expended In 2014, an RI/FS (Bay West, 2014a) was developed to evaluate remedial options for soil contaminated with lead. Details of the findings of the RI are provided in Section 2.5.8. In November 2014, the RI/FS and Proposed Plan (PP) were made available to the public and a public meeting was held on 1 December 2014. The PP identified the Preferred Alternative “Land Use Controls” for soil at the SHSAR Impact Slope MRS (Bay West, 2014b). Figure 2-2 presents a general timeline of MRS history, investigations, and actions. No other remedial activities have occurred at the MRS. There have been no USEPA or KDHE enforcement activities related to the MRS. Figure 2-2 Timeline of MRS History, Investigations, and Actions
1880 Late 1980s - Late 1980s 1994 Firing early 1990s Soil 2005 2010-2011 2014 2014 Firing range Residential sampling Site RI field RI/FS Proposed activities activities development and lead Inspection work Report Plan cease start begins removal
2.3 Community Participation NCP Section 300.430(f)(3) establishes a number of public participation activities that the lead agency must conduct during the remedy selection process. Components of these activities and
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Table 2-2 Public Notification of Document Availability Requirement Satisfied by Notice of availability of the PP, RI/FS must be made in a Notice of availability was published on 15 general circulation major local newspaper. November 2014, in the Junction City Daily Union News, Junction City, Kansas, and on 18 November 2014 in the Manhattan Mercury, Manhattan, Kansas. Notice of availability must include a brief abstract of the PP, The notice of availabilities included the which describes the alternatives evaluated and identifies the required components and is included for preferred alternative (NCP Section 300.430[f][3][i][A]). reference as Attachment 2.
Table 2-3 Public Comment Period Requirements Requirement Satisfied by Lead agency should make document available to public for The PP was made available to the public review on same date as newspaper notification. on 15 November 2015. Lead agency must ensure that all information that forms the Fort Riley maintains the Administrative basis for selecting the response action is included as part of Record file for the MRS at Fort Riley and the Administrative Record file and made available to the at the Manhattan Public Library. Data public during the public comment period. collected and CERCLA primary documents produced for the MRS were placed therein and made available to the public at those locations. CERCLA Section 117(a)(2) requires the lead agency to The Army provided a public comment provide the public with a reasonable opportunity to submit period for the PP and other supporting written and oral comments on the PP. information from 15 November 2014 to NCP Section 300.430(f)(3)(i)(C) requires the lead agency to 16 December 2014 (30 days). allow the public a minimum of 30 days to comment on the RI/FS, PP, and other supporting information located in the Administrative Record. The lead agency must extend the public comment period by The Army received no requests to extend at least 30 additional days upon timely request. the public comment period. The lead agency must provide the opportunity for a public The Army held a public meeting on meeting to be held at or near the MRS during the public 1 December 2014 at Fort Riley’s comment period. Conference Center, 446 Seitz Drive, Fort Riley, Kansas, to accept oral and written comments. A copy of the transcript is included as Attachment 3. The lead agency should solicit community input on This information was solicited during the reasonably anticipated future land use and potential public meeting. No additional information beneficial groundwater uses at the site. from the public was obtained. One comment from the public was received during the public meeting. This comment is addressed in the Responsiveness Summary in Section 3.0. No additional comments were received during the public comment period.
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2.4 Scope and Role of MRS or Response Action In 2002, the U.S. Congress established the Military Munitions Response Program (MMRP) under DERP to address MEC and munitions constituents (MC) located on current and former defense sites. The SHSAR Impact Slope MRS was determined to be eligible for action under the DERP-MMRP (10 United States Code [U.S.C.] 2701). The residual explosive hazards associated with MEC following the RI, wherein a full coverage surface clearance and subsurface investigation occurred, were determined to be very low and not warranted further action. Management of MC (i.e., lead) at the SHSAR Impact Slope MRS under DERP-MMRP is being conducted by the Army in accordance with CERCLA, as amended by SARA, and NCP. Based on the information and data collected for the MRS, the Army anticipates that the selected remedy will protect the public and environment from the hazards related to MC (i.e., lead) present in the surface soils. The scope and role of the response action is to reduce hazards associated with lead contamination to human health and the environment based on current and intended future land use. MEC hazards were determined to be low and do not require further action. The SHSAR Impact Slope MRS is the one of two MRSs currently being investigated at Fort Riley. The other MRS is being addressed separately and does not impact the decisions made for the SHSAR Impact Slope MRS. The selected remedy is intended to be the final remedy for the MRS and does not impact any other areas at Fort Riley.
2.5 Site Characteristics 2.5.1 Topography Three types of physiographic areas are found at Fort Riley. They are high upland tall grass prairies, alluvial bottomland floodplains, and broken and hilly transition zones. Alternating layers of Permian-aged limestone and shale dominate the uplands. The softer shale units eroded at a significantly faster rate than the more resistant limestone escarpments, which form the broken and hilly transition areas of the central and east portions of the Post. The cutting action of the streams on the thick shale units has sculpted much of the area into a rolling plateau. Fort Riley is composed of two types of alluvial bottomlands: wide meandering floodplains of major rivers with associated terraces, and areas created by smaller creeks and streams that cut the uplands (Burns and McDonnell, 2001). The SHSAR Impact Slope MRS consists of a steeply sloping ridge that rises from approximately 1,180 ft to 1,280 ft above mean sea level (msl). 2.5.2 Climate Fort Riley has a temperate continental climate characterized by hot summers, cold dry winters, moderate winds, low humidity, and a pronounced peak in rainfall late in the spring and first half of summer. Prevailing winds are from the south to southwest during most of the year, except during February and March when the prevailing winds are from the north. Temperatures in the Fort Riley area vary widely and often fluctuate abruptly throughout the year. July and August are the hottest months, averaging 80 degrees Fahrenheit (°F). January is the coldest month, averaging 26°F. The average date of the last killing frost in spring is 22 April, and the average date of the first killing frost of the fall is 17 October. The area has an average of 180 frost-free days per year.
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Average yearly precipitation is 31.64 inches, and most of the precipitation (75 percent [%]) falls in the 6-month period from April through September. The three highest rainfall months (May, June and July) each average over 4 inches per month. Much of this precipitation occurs during severe thunderstorms, when 2 inches or more of rain may fall in one storm. December, January, and February are the driest months, with each averaging less than 1.56 inches of liquid equivalent precipitation. An average of 22 inches of snowfall occurs annually. Insufficient precipitation is the major limiting factor to plant growth at Fort Riley. Spring rains are normally adequate to recharge soil moisture. During the summer months, evapotranspiration rates normally exceed precipitation rates, especially in the latter half of the summer. In years of below average rainfall, soil moisture in the upper soil levels is depleted, which stresses shallow rooted plants (Burns and McDonnell, 2001). 2.5.3 Geology and Hydrology Fort Riley is underlain by bedrock of Pennsylvanian (in deeper subsurface) and Permian age. The bedrock is composed of the Chase Group (Upper Permian), which is exposed at the ground surface in many areas or covered by a thin mantle of loess (wind-blown silts). Older Permian rocks of the Council Grove Group are limited to the southeastern portion of the Fort Riley. The Permian bedrock units consist of alternating layers of shale and limestone. The Barneston and Winfield Formations underlie most of the Post; both units contain limestone and shale members. The more prominent bedrock outcrops at Fort Riley are composed of the Fort Riley Limestone Member of the Barneston Limestone which, due to its 30-ft thickness and chert-free character, is resistant to erosion. The Barneston Limestone Formation is visible in many stream banks as white, wall-like exposures. The Fort Riley Limestone is prominent as the rim rock outcrop that has a wall-like appearance near the top of bluff lines. The overall thickness of the Fort Riley Limestone Member is typically 30–45 ft and is a massive- to thin-bedded limestone with minor basal shale planes evident in the bedrock. Quaternary-aged alluvial sand and gravel deposits are present in river floodplains. The alluvial deposits of the Republican River consist of clay, silt, and sand near the surface and coarser sands and gravel at depth. The alluvial deposits are underlain by limestones and shales (Burns and McDonnell, 2001). 2.5.4 Hydrogeology Alluvial sand and gravel deposits in the Fort Riley area serve as excellent aquifers. Water table maps indicate that the direction of groundwater flow in the alluvial aquifer generally flows south down the valley towards the Republican River, but can be highly variable near the Kansas and Republican Rivers in the Fort Riley vicinity. Groundwater levels in the alluvial aquifer are affected primarily by the stage of the Republican River and, to a lesser extent, by the stage of tributaries, ponds, and lakes, and by infiltration from precipitation. The correlation between Republican River stage and groundwater levels in the alluvial aquifer is strongest near the river and is weaker farther from the river. The six cantonment areas of Fort Riley and the surrounding communities of Junction City, Ogden, and Manhattan rely on groundwater withdrawn from alluvial materials. Fort Riley has eight active water supply wells. In the upland areas, limestone formations are identified as groundwater sources. Inflow of groundwater from adjacent bedrock aquifers contributes a small but important component of groundwater to the alluvial aquifer in the valley.
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The town of Riley and many rural residences surrounding Fort Riley are located in the uplands area and their wells tap bedrock formations. Groundwater in the uplands area is generally present within 100 ft of the ground surface. For example, the town of Riley uses seven wells ranging in depths from 90–100 ft, and these wells draw water from the limestone formations. In general, the limestone formations are sufficiently transmissive to yield reliable groundwater supplies. During the RI, depth to groundwater at the SHSAR Impact Area MRS was determined to be 50 to 60 ft below ground surface (bgs). 2.5.5 Hydrology Surface waters on Fort Riley are within the Kansas River and Republican River drainage basins. Intermittent and perennial creeks, ponds, lakes, and rivers are represented at Fort Riley. Milford Lake is a reservoir on the western edge of the Post that impounds the Republican River. With 15,600 surface acres of water and 163 miles of shoreline, it is the most notable water body in the immediate Fort Riley area. Fort Riley has 174 lakes and ponds ranging in size from 0.1 to 40 acres. With the exception of three oxbow lakes, the lakes and ponds on the Post are man-made. Approximately 50% of these impoundments are intermittent and hold little water except during very wet years. Fort Riley manages 29 lakes and ponds to provide fishing opportunities for civilian and military personnel. No significant surface water bodies exist within 1 mile of the SHSAR Impact Slope MRS. Moon Lake, drinking water plant, and the lime sludge monofill are immediately northeast of Sherman Heights. There are no wetlands areas within or adjacent to the MRS. Surface water runoff at Fort Riley runs to, and is drained by, the Republican River, Kansas River, Threemile Creek, Sevenmile Creek, Honey Creek, Wildcat Creek, and numerous smaller tributaries. The Republican River runs along the southern boundary of Fort Riley. The Colyer Manor housing area sits atop alluvial deposits associated with the river that extend to the toe of the adjacent SHSAR Impact Slope MRS. Fort Riley has 14 named creeks, 10 of which have perennial flow. Numerous unnamed intermittent and ephemeral creeks are also present (Burns and McDonnell, 2001). 2.5.6 Vegetation This region consisted of tall- and mixed-grass prairies dominated by big bluestem (Andropogon gerardi), indiangrass (Sorghastrum nutans), and switchgrass (Panicum virgatum) under natural conditions. The presettlement prairie was maintained through periodic wildfires and grazing by herbivores. Woodlands were present within moist bottomlands of floodplains and along perennial stream corridors. However, past and current land management practices, such as the suppression of wildfires, the introduction of agriculture and stock grazing, and the construction and expansion of military facilities have resulted in the establishment and expansion of several vegetation classes at Fort Riley. The five broad categories of land cover on Fort Riley are grassland, shrublands, forestlands, savannas, and croplands. As of 2002, 233 plant species from 178 genera and 59 families have been collected and preserved at Fort Riley. The number of plant species identified at Fort Riley is expected to increase as surveying and collection efforts continue. (e2M, 2006)
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Ground cover at the SHSAR Impact Slope MRS ranges from exposed bedrock to grass interspersed with small trees. One overhead utility line transects (north-south) the MRS near the midpoint. The MRS is located between the Colyer Manor military family housing complex and the Sherman Heights highlands. (e2M, 2006) 2.5.7 Ecology Fort Riley habitat supports at least 43 species of mammals, 223 species of birds, 41 species of reptiles and amphibians, and 50 species of fish. Many of these species are year-round residents, although most of the birds are seasonal migrants. (e2M, 2006) Only four federally listed endangered or threatened species have been observed at Fort Riley. Three of the species are birds: the bald eagle (Haliaeetus leucocephalus), least tern (Sterna antillarum), and piping plover (Charadrius melodus). The bald eagle winters on Fort Riley, and the other two species are uncommon migratory transients. The fourth species is the Topeka shiner (Notropis topeka). The Topeka shiner, a minnow, has been found in Wildcat, Sevenmile, Wind, Honey, and Little Arkansas creeks, all of which are streams on the eastern side of the Installation. (e2M, 2006) 2.5.8 Nature and Extent of Contamination Several environmental investigations have been performed at the MRS to determine the nature and extent of contamination. The results from these studies are shown in Table 2-4. Table 2-4 Previous MRS Characterization Activities Summary
Study Activities Major Findings 1994 X-ray Soil sampling for MEC: No MEC was encountered. fluorescence lead MC: Sampling was focused to the Colyer Manor residential housing (XRF) Sampling Soil removal area, but extended into the southern portion of the SHSAR Impact & Confirmatory Slope MRS. Approximately 1,500 cubic yards of soil was removed. Sampling The majority of this soil was south of the SHSAR Impact Slope MRS (OHM, 1994) boundary. 2005 SI Visual/ MEC: During a preliminary site visit in April 2005, approximately 15 (e2M, 2006) magnetometer Material Potentially Presenting an Explosive Hazard (MPPEH) items, surveys for MEC including 4-inch Stokes practice mortars, were observed on the impact Surface and slope. These potential MEC items were removed by Fort Riley subsurface soil personnel prior to the SI field activities that were conducted on 11 July sampling for lead 2005. During the July 2005 survey, an additional 4-inch practice mortar was identified. All of the items identified were partially detonated (i.e., the charges were fully burned but the casings did not fully fragment). As such, the items were determined to be Material Documented as Safe (MDAS) and no MEC was identified. However, based on the findings, further evaluation of MEC was recommended. MC: Surface soil samples collected from the MRS did not contain concentrations of explosives greater than detection limits; however, one surface soil sample (collected adjacent to an in situ mortar) contained lead (657 mg/kg) and zinc (49,500 mg/kg) at concentrations that exceeded the residential screening levels of 400 mg/kg and 23,000 mg/kg, but below the industrial screening levels of 800 mg/kg and 310,000 mg/kg, respectively. Further evaluation of MC was recommended. 2010-2011 52-acre MEC MEC: One MD item, a 4-inch Stokes practice mortar, was recovered RI/FS (Bay surface clearance during the surface clearance. Three MEC items (a 3-inch Mk 3 Mod 7 West, 2014a) Full coverage common projectile, a 3-inch Hotchkiss projectile, and a 2.36-inch M6 digital geophysical anti-tank rocket) and 597 pounds (lbs) of MD were recovered during
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Table 2-4 Previous MRS Characterization Activities Summary
Study Activities Major Findings mapping (DGM) or the intrusive investigation. The net effect of the investigation was a mag and dig removal action; therefore, a no further action determination for MEC All targets was recommended. The results from the MEC investigation are shown intrusively on Figure 2-3. investigated MC: Groundwater and soil sampling was performed, as shown on XRF and Figure 2-4. Groundwater samples were collected from the center of laboratory soil the MRS and were located in areas designed to achieve spatial sampling for lead, distribution in the central lead-impacted area. No contaminants were explosives and/or detected in groundwater exceeded any screening levels. No Resource explosives were detected in the soil samples. Arsenic, chromium, and Conservation and lead concentrations in soil exceeded screening levels; however, Recovery Act arsenic did not exceed KDHE Tier 2 Risk-Based Residential Standard (RCRA) metals and chromium did not exceed background. The initial round of plus copper, incremental sampling (IS) identified areas where lead exceeded the excluding mercury KDHE Tier 2 Risk-Based Residential Standard and USEPA Groundwater Residential RSL of 400 mg/kg. Supplemental sampling for lead using samples for RCRA XRF with fixed laboratory analysis was performed to further refine the metals (excluding nature and extent of lead in the two IS areas where lead was detected mercury) and above the KDHE Tier 2 Risk-Based Residential Standard and USEPA explosives RSL of 400 mg/kg, commercial/ industrial RSL of 800 mg/kg, and the KDHE Tier 2 the Non-residential Standard of 1,000 mg/kg. The lead concentrations ranged from 61 to 38,000 mg/kg.
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Figure 2-3 MEC/MD Locations Reported from Previous Investigations
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Figure 2-4 RI MC Sample Locations and Results
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Based on the results from the environmental studies summarized in Table 2-4, it was concluded that there is only a low risk for MEC exposure, so no further evaluation of MEC was recommended. However, environmental impacts associated with lead in surface soils have occurred. The impacted area is approximately 5.5 acres and extends approximately 0.5 ft bgs, equating to approximately 4436.7 cubic yards of impacted soil as shown in Figure 2-4.
2.6 Current and Potential Future Land Use and Resource Uses The SHSAR Impact Slope MRS is undeveloped. Ground cover ranges from exposed bedrock to grass interspersed with small trees. Access to the SHSAR Impact Slope MRS is currently unrestricted; however, the rugged nature of the ridge limits access by foot traffic. A dirt road runs from a drinking water treatment plant located north of the SHSAR Impact Slope MRS, across the northeast portion at the top of the ridge. Access from the lower side of the SHSAR Impact Slope MRS is by foot from the north side of the Colyer Manor military family housing complex. Groundwater at the SHSAR Impact Slope MRS and downgradient of the MRS is currently not used as a potable water source. The Colyer Manor military family housing complex is connected to Fort Riley water supply wells located upgradient of the MRS in the uplands area. Potential for expanded use of the Impact Slope in the future is limited by terrain and the SHSAR Impact Slope MRS’s proximity to the Colyer Manor military family housing area. Though future residential land use is not planned and the physical characteristics of the slope limit development, the MRS is close to Post housing and has unrestricted access by residents, particularly children playing within the MRS area. 2.6.1 Conceptual Site Model Using the MRS characteristics, nature and extent of contamination, land use, exposure route, and receptors, graphical depictions of the conceptual site model (CSM) for MEC and MC were developed for the MRS illustrating current and future risks to human health and the environment and is shown on Figure 2-5 (MEC) and Figure 2-6 (MC). In summary, three MEC items were identified during the RI investigation. While there is potential for MEC exposure because the MRS has unlimited access, this pathway is considered incomplete because the items found during the earlier SI and during this RI were removed, and no additional MEC items were identified in the remaining area of the MRS during the RI. Therefore, the SHSAR Impact Slope MRS is deemed low risk for MEC exposure based on the historic information and findings presented in this report. As a result, the exposure pathways for MEC were all considered incomplete. Potential exposure pathways for MC include soil, groundwater, and air. MC is found in soils contaminated with the finer fraction (i.e., particles) of lead and associated metals, as well as constituents contained in the primer of bullet slugs, mortars, shell casings, and expended or unexpended smoke canisters. Since lead was detected in surface soil samples, the soil and air exposure pathways are potentially complete. Dermal contact, dust inhalation, and incidental ingestion are the routes through which exposure to contaminated soil may occur. The groundwater exposure pathway is considered to be potentially complete because groundwater in the vicinity is used as a potable water supply. However, due to the geology, depth to groundwater, limited precipitation, and limited contaminant mobility, there is little potential for groundwater contamination from the soil.
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Figure 2-5 MEC Exposure Conceptual Site Model
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Figure 2-6 MC Exposure Conceptual Site Model – Human Receptors
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2.7 Summary of Site Risks At the conclusion of the RI, it was determined that explosives hazards associated with MEC are not likely present. As such, no unacceptable human health or environmental hazards associated with MEC are present. Therefore, a MEC hazard assessment (MEC-HA) was not required to be performed. 2.7.1 Summary of the Human Health Risk Assessment A human health risk assessment (HHRA) was completed as part of the RI to evaluate risk to human health associated with contaminants in soil and groundwater assuming baseline conditions (i.e., no remedy is implemented for existing chemical contamination). The baseline HHRA followed USEPA and state guidance including Risk Assessment Guidance for Superfund (RAGS), Volume I, Human Health Evaluation Manual, (Part A) (USEPA, 1989); Risk-Based Standards for Kansas RSK Manual, 5th Version (KDHE, 2010); and May 2013 Regional Screening Table User’s Guide (USEPA, 2013). The basic steps of the HHRA include data evaluation, exposure assessment, toxicity assessment, and risk characterization, which are described in the following subsections. 2.7.1.1 Data Evaluation The data evaluation reviews and evaluates available data and identifies chemicals of potential concern (COPCs) included in the quantitative exposure estimation and risk characterization steps of the HHRA. The soil and groundwater data used in the risk assessment were collected in 2010 and 2011 as part of the SHSAR Impact Slope MRS RI. Samples were analyzed for total Resource Conservation and Recovery Act (RCRA) metals (excluding mercury) and explosives; explosives were not detected. Chemicals were selected as COPCs if the maximum reported concentration exceeded the soil or groundwater screening level. Soil screening levels were the USEPA June 2013 RSLs for residential soil; groundwater screening levels were the USEPA June 2013 RSLs for tap water. To evaluate contribution from multiple contaminants, the non- cancer RSLs were reduced by a factor of 10 to reflect a hazard quotient (HQ) of 0.1, following USEPA (2013) guidance. On-site concentrations of other inorganic chemicals in soil were also compared with background data collected from the Impact Slope to determine which inorganic COPCs have concentrations within ambient levels. Inorganic contaminant concentrations that are less than or equal to background levels were excluded as COPCs. Arsenic, chromium, and lead concentrations exceeded RSLs; however, chromium did not exceed background. The maximum arsenic concentration (5 mg/kg) was slightly above background (4.6 mg/kg), but does not exceed the KDHE Tier 2 level for residential soil (11.3 mg/kg) so arsenic was excluded as a COPC. Therefore, only lead is considered a human health COPC in soil. Groundwater concentrations were also compared to the USEPA maximum contaminant levels (MCLs) and KDHE Tier 2 risk-based groundwater levels. No contaminants in groundwater exceeded screening levels, so groundwater was not evaluated further in the HHRA. 2.7.1.2 Exposure Assessment The exposure assessment characterizes potentially exposed human populations in the area associated with the MRS to identify actual or potential exposure pathways, and quantifies the extent of exposure. Based on current and anticipated future land use, the potential receptors at this MRS are likely to include Fort Riley residents, Post personnel and contractors, recreational users, and construction workers. Because there are residences in close proximity to the impact slope, both residential and nonresidential scenarios were considered in the baseline HHRA. While residential land use is not anticipated, potential future residents were evaluated such that unrestricted reuse could be evaluated to support no further action decisions at this MRS, if
W9128F-09-D-0059, TO 0009 2-16 January 2016 BWJ130451 Revision 03 Record of Decision Sherman Heights Small Arms Range Impact Slope Fort Riley, Kansas appropriate. In general, exposure of other receptors (e.g., recreational users/construction workers) would be infrequent and intermittent and therefore significantly less than a resident or non-residential worker. Since elevated levels of lead were detected in surface soil samples, direct contact with soil is a potentially complete exposure pathway. USEPA evaluates direct exposure with lead in soil by using blood lead modeling, such as the Integrated Exposure Uptake Biokinetic Model (IEUBK) for Lead in Children and the Adult Lead Model (ALM). The residential RSL was developed using the IEUBK model, and the commercial/industrial RSL was developed using the ALM. The USEPA applied standard intake assumptions for residential and commercial/industrial land use in these models to develop the residential and commercial/industrial RSLs for lead. The ALM was also used to evaluate the recreational/construction worker exposure scenario. The intake assumptions for this receptor group are the default outdoor soil ingestion rate of 100 milligrams per day (mg/day) for ages 6 years and older (USEPA, 1991) and an exposure frequency (EF) of 90 days per year. All remaining ALM default values were applied (USEPA, 2009). This EF is the minimum value that can be used in the ALM, and is appropriate for this site based on limited access to the slope due its rugged nature and to cold weather during winter months that will limit outdoor activities. An EF of 90 days/year is approximately equivalent to an exposure of 2 days per week for 4.3 weeks per month for 10 months per year. Exposure to lead in soil was assessed for each receptor group using both the maximum detected concentration and the 95% upper confidence limit (UCL) of the mean. The 95% UCL is generally used in CERCLA risk assessments to represent a reasonable maximum estimate of the concentration a receptor is likely to be exposed to over time. The 95%UCL was calculated using USEPA (2010a) ProUCL (Version 4.1.01). Both incremental samples and discrete X-ray fluorescence (XRF) samples were collected during the RI; the 95% UCL COPC concentration was calculated from the incremental samples collected from the 16 sampling units (SUs) within the SHSAR Impact Slope MRS decision unit, and the 95% UCL was also calculated separately for the XRF laboratory correlation samples. To account for the differences in sampling techniques, the maximum detected concentration of each dataset was used in the risk calculations. Use of the maximum and 95% UCL concentrations is conservative because the IEUBK and the ALM recommends use of an arithmetic mean concentration of sampling data. 2.7.1.3 Toxicity Assessment Toxicity assessment involves a review of agency literature and the subsequent compilation of cancer and non-cancer toxicity values (e.g., cancer slope factors) and non-cancer references doses [RfDs]) used to estimate cancer risk and non-cancer hazard index. USEPA’s risk assessment for lead is unique because an RfD value for lead is not available (USEPA, 2012a). Existing evidence indicates that adverse health effects occur even at very low lead exposures (e.g., subtle neurological effects in children have been observed at low doses). The USEPA identifies a blood lead concentration level of 10 micrograms per deciliter (μg/dL) as the level of concern above which significant health risks occur (USEPA, 2012a). The USEPA risk reduction goal for contaminated sites is to limit the probability of a child’s blood lead concentration exceeding 10 μg/dL (the P10) to 5% or less after cleanup (USEPA, 2012a). 2.7.1.4 Risk Characterization Risk characterization typically estimates the potential excess lifetime cancer risk and potential for non-cancer adverse health effects for human receptors exposed to COPCs in soil within the SHSAR Impact Slope MRS. Due to the lack of standard toxicity values for lead, evaluation of risk from exposure to lead was conducted by comparing the concentrations of lead in soil to RSLs for residential (400 mg/kg) and commercial/industrial land use (800 mg/kg). The KDHE
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Tier 2 levels for lead are 400 mg/kg for residential and 1,000 mg/kg for non-residential scenarios. Lead concentrations exceeding the residential and commercial/industrial RSLs were considered to represent a potential unacceptable level of health risk to residents, Post personnel and contractors. In addition, a risk-based concentration of 2,725 mg/kg was developed for a recreational/ construction worker using the USEPA ALM. Lead concentrations exceeding this risk-based screening level were considered to represent a potential risk to a recreational user and a construction worker. Residential Receptor Group: For the residential receptor, the residential RSL of 400 mg/kg was exceeded by the maximum incremental sample concentration (Table 2-5). The 95% UCL concentration of lead in incremental samples (527.6 mg/kg) exceeds the residential RSL. For the XRF laboratory correlation samples, the residential RSL of 400 mg/kg was exceeded by the maximum XRF sample concentration. The 95% UCL concentration of lead (11,311 mg/kg) exceeds the residential RSL. Accordingly, lead within SHSAR Impact Slope was found to represent a potential unacceptable level of health risk to a hypothetical future residential receptor. Table 2-5 Lead Concentrations Compared to Human Health Risk-Based Screening Levels Number of Samples Exceeding Risk-Based Screening Level Maximum 95% ALM Commercial/ Concentration UCL Residential Recreational/ Industrial (mg/kg) (mg/kg) RSL (400 Construction a RSL (800 mg/kg) Worker RBC mg/kg)a (2,725 mg/kg) Lead - Incremental 1,300 527.6 2 1 0 Samples Lead - XRF lab 38,000 11,311 17 9 4 correlation a USEPA June 2013 Regional Screening Level (RSL) for soil * Excludes field duplicates in total sample count RBC – risk-based concentration
Post Personnel and Contractor Receptor Group: The commercial/industrial RSL of 800 mg/kg was exceeded by the maximum incremental sample concentration, but the 95% UCL concentration of lead in incremental samples (527.6 mg/kg) does not exceed the commercial/industrial RSL. The commercial/industrial RSL was exceeded by the maximum XRF sample concentration. The 95% UCL concentration of lead (11,311 mg/kg) exceeds the commercial/industrial RSL. Accordingly, lead within SHSAR Impact Slope was found to represent a potential health risk to Post personnel and contractors. Recreational User and Construction Worker Receptor Group: The USEPA ALM model was used to evaluate risk to recreational users and construction workers by estimating the probability of fetal blood lead concentration of the pregnant female worker exceeding the threshold of 10 μg/dL. At the maximum detected lead concentration (1,300 mg/kg) in the incremental samples, the ALM calculated an adult worker blood lead level of 2.5 μg/dL and predicted that there would be a 0.6% chance that the fetus of a pregnant adult worker would have a blood lead level above 10 μg/dL. At the 95% UCL lead concentration (527.6 mg/kg), the ALM calculated an adult worker blood lead level of 1.6 μg/dL and predicted that there would be
W9128F-09-D-0059, TO 0009 2-18 January 2016 BWJ130451 Revision 03 Record of Decision Sherman Heights Small Arms Range Impact Slope Fort Riley, Kansas a 0.1% chance that the fetus of a pregnant adult worker would have a blood lead level above 10 μg/dL. Thus, lead concentrations in the ISs were found not to pose risk to recreational/ construction worker. For the XRF laboratory correlation samples, at the maximum detected lead concentration (38,000 mg/kg) the ALM calculated an adult worker blood lead level of 46.0 μg/dL and predicted that there would be a 99.2% chance that the fetus of a pregnant adult worker would have a blood lead level above 10 μg/dL. At the 95% UCL lead concentration (11,311 mg/kg), the ALM calculated an adult worker blood lead level of 14.4 μg/dL and predicted that there would be a 67% chance that the fetus of a pregnant adult worker would have a blood lead level above 10 μg/dL. Thus, lead concentrations in the XRF laboratory correlation samples were found to pose risk to recreational/construction worker. The ALM was also used to calculate a risk-based concentration (RBC) for a non-residential setting that is intended to protect a fetus carried by a pregnant female worker. It assumes a cleanup goal protective of a fetus also affords protection for male or female adult workers (USEPA, 2011b). For the recreational/construction worker receptors, the RBC is 2,725 mg/kg of lead. None of the incremental samples were found to exceed the recreational/construction worker RBC. Four XRF laboratory correlation samples were found to exceed the recreational/construction worker RBC of 2,725 mg/kg lead. 2.7.1.5 Interpretation and Conclusions The risk evaluation for human health led to the following conclusions: No COPCs were identified in groundwater. Solubility of lead in groundwater is limited, and the water wells at the site are tested regularly and no lead is present. Lead is the only contaminant of concern in soil. Other metals were not detected at levels of concern and explosives were not detected at the limit of detection. The lead is in the form of inorganic projectiles, principally pistol rounds, which were fired at targets set against the bluff. Additionally, the soils are bicarbonate soils that form a covering of lead carbonate on any free metal lead present. The lead carbonate is extremely insoluble with a solubility product of 1x10-13. Recreational users/construction workers represent the most probable human populations likely to be present. Fort Riley residents, Post personnel, and contractors represent the human populations less likely to be present in the area. Lead in soil at SHSAR Impact Slope MRS poses an unacceptable risk to human health from exposure to lead in soil under future residential use and under current/future non- residential use. Two IS SUs pose risk having concentrations greater than 400 mg/kg lead. Numerous XRF correlation sample locations were collected to further refine the nature and extent of contamination lead contamination within the two IS SUs where lead was detected above 400 mg/kg. Nine XRF locations detected lead concentrations greater than 800 mg/kg lead. Therefore, lead in these areas is the primary source of unacceptable level of risks to human health. The residential RSL will provide for unrestricted reuse of the property. However, time spent (and therefore cumulative exposures to COPCs) is likely higher for a resident than for any of the other human receptors expected at the MRS, and use of residential RSL is likely to overestimate potential impacts associated with exposure to lead at the SHSAR Impact Slope MRS.
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2.7.2 Summary of the Ecological Risk Assessment This section summarizes the focused screening level ecological risk assessment (SLERA) that was completed as part of the RI to assess potential adverse impacts on current or future ecological receptors exposed to MC in surface soil. The assessment endpoint for the SLERA was the protection of local populations and communities of biota from adverse impacts from explosives and metals in soil. 2.7.2.1 Ecological Screening Criteria USEPA has developed risk-based ecological soil screening levels (Eco-SSLs) that are concentrations of contaminants in soil that are protective of ecological receptors that commonly come into contact with soil or ingest biota that live in or on soil (USEPA, 2005a). Eco-SSLs are derived separately for four groups of ecological receptors: plants, soil invertebrates, birds, and mammals. Eco-SSLs for each receptor group were considered in the selection of initial chemicals of potential ecological concern (COPEC). 2.7.2.2 Media Screening Results Analytical IS laboratory data and XRF laboratory correlation data generated during the RI were compared to Eco-SSLs to determine if contaminant releases have occurred at concentrations exceeding levels of potential concern (Table 2-6). Only inorganic constituents were evaluated because all explosives were non-detect at the limit of detection. All chemicals that exceed the conservative screening level were identified as COPECs. For the IS dataset, copper exceeded the avian, mammalian, soil invertebrate, and plant ecological screening level; and lead concentrations exceeded the lowest ecological screening level for avian, mammalian, and plant receptors. All lead concentrations in the XRF correlation samples exceeded the lowest ecological screening level. Cadmium exceeded the mammalian ecological screening level but did not exceed ecological screening levels for plants, soil invertebrates or birds. Therefore, copper, lead and cadmium were identified as COPEC and were evaluated further in the SLERA. Table 2-6 Screening of Chemicals of Potential Ecological Concern
Incremental Sample Ecological Soil Screening Levels (EcoSSL) Maximum COPEC Results Avian Mammal Invertebrates Plants Inorganics (mg/kg) Arsenic 5 43 46 -- 18 No; BSL Barium 100 -- 2,000 330 -- No; BSL
Cadmium 0.65 0.77 0.36 140 32 Yes; ASL 34 (III); Chromium 13 26 -- -- No; BSL 130 (VI) Copper 89 28 49 80 70 Yes; ASL Lead 1,300 11 56 1,700 120 Yes; ASL Selenium 1.5 U 1.2 0.63 4.1 0.52 No; ND Silver 0.2 U 4.2 14 -- 560 No; ND
Explosives (mg/kg)
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Incremental Sample Ecological Soil Screening Levels (EcoSSL) Maximum COPEC Results Avian Mammal Invertebrates Plants None detected above the limit of detection
XRF Laboratory Correlation Results Lead - XRF lab correlation 38,000 11 56 1700 120 Yes; ASL BSL - below screening level ASL - above screening level ND - not detected. 2.7.2.3 Special Status Species or Locations The SHSAR Impact Slope MRS does not contain sensitive natural resources (i.e., federally- listed as threatened or endangered species or federally-listed critical habitat). Several Army Species at Risk (SAR) occur on Fort Riley (Henslow’s sparrow [Ammodramus henslowii], regal fritillary [Speyeria idalia], rusty blackbird [Euphagus carolinus], and Texas horned lizard [Phrynosoma cornutum]); (Integrated Natural Resources Management Plan [INRMP], Fort Riley, 2010). Several Kansas designated Species in Need of Conservation (SINC) have been documented on Fort Riley including the prairie mole cricket (Gryllotalpa major), blue sucker (Cycleptus elongatus), common shiner (Luxilus cornutus), Johnny darter (Etheostoma nigrum), southern redbelly dace (Chrosomus erythrogaster), western hognose snake (Heterodon nasicus), black rail (Laterallus jamaicensis), black tern (Chlidonias niger), bobolink (Dolichonyx oryzivorus), ferruginous hawk (Buteo regalis), golden eagle (Aquila chrysaetos), Henslow’s sparrow (Ammodramus henslowii), short-eared owl (Asio flammeus), whip-poor-will (Antrostomus vociferous), and southern bog lemming (Synaptomys cooperi) (Fort Riley, 2010). 2.7.2.4 Hazard Quotient Evaluation The HQ method was used to evaluate the potential risk to higher level organisms from cadmium, copper, and lead in soil, following methods presented in the Eco-SSL guidance documents (USEPA, 2005b; 2005c; 2007). The HQ is equal to the estimated exposure dose of an ecological receptor divided by a toxicity reference value (TRV). Following Eco-SSLs methods and applying exposure parameters provided in the Eco-SSL guidance documents, six wildlife receptor groups (and associated surrogate species) were evaluated, including mammalian herbivores (meadow vole), mammalian carnivores (long-tailed weasel), mammalian omnivores (short-tailed shrew), avian granivores (mourning dove), avian carnivores (red-tailed hawk), and avian omnivores (American woodcock). Exposure to cadmium, copper, and lead was assessed for each receptor group using both the maximum detected concentration and the 95% UCL of the mean. The TRV used in Eco-SSL development represents a receptor-class specific estimate of a no observed adverse effect level (NOAEL) for the respective contaminant for chronic exposure. An HQ less than 1 based on a NOAEL-based TRV indicates little or no ecological risk. Calculation of an upper bound HQ using lowest observed adverse effect level (LOAEL) toxicity values was done to refine screening level risk estimates and to provide a range of ecological hazard. A LOAEL-based TRV represents a dose that is expected to produce adverse population effects. The HQs for exposure to COPEC in soil are provided in Table 2-7.
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Table 2-7 COPEC Risk Characterization for Various Soil Concentrations
Avian ground Mammalian ground Mammalian ground Mammalian Avian herbivore Avian carnivore insectivore insectivore herbivore carnivore Copper Soil (American (Long-tailed (Mourning dove) (Red-tailed hawk) (Short-tailed shrew) (Meadow vole) Concentration (mg/kg) woodcock) weasel) HQ - HQ - HQ - HQ - HQ - HQ - HQ - HQ - HQ - HQ - HQ - HQ - NOAEL LOAEL NOAEL LOAEL NOAEL LOAEL NOAEL LOAEL NOAEL LOAEL NOAEL LOAEL Maximum 89 3.2 0.37 0.94 0.11 0.07 0.01 1.8 0.14 0.16 0.01 0.15 0.01 95% UCL 41.46 1.5 0.17 0.54 0.06 0.04 0.005 0.8 0.06 0.11 0.01 0.09 0.01 Cadmium Soil HQ - HQ- HQ - HQ- HQ - HQ- HQ - HQ- HQ - HQ- HQ - HQ- Concentration (mg/kg) NOAEL LOAEL NOAEL LOAEL NOAEL LOAEL NOAEL LOAEL NOAEL LOAEL NOAEL LOAEL Maximum 0.65 0.57 0.13 0.09 0.02 0.01 0.003 1 0.12 0.07 0.01 0.08 0.01 95% UCL 0.448 0.42 0.1 0.07 0.02 0.01 0.002 0.77 0.09 0.06 0.01 0.07 0.01 Lead Soil HQ - HQ - HQ - HQ - HQ - HQ - HQ - HQ - HQ - HQ - HQ - HQ - Concentration (mg/kg) NOAEL LOAEL NOAEL LOAEL NOAEL LOAEL NOAEL LOAEL NOAEL LOAEL NOAEL LOAEL Residential RSL 400 22 0.82 8.1 0.3 0.81 0.03 5.2 0.17 0.49 0.02 0.88 0.03 XRF Correlation Lab Samples Maximum 38000 1365 50 636 23 49 1.8 236 7.6 26 0.84 48 1.6 detected 95% UCL 11311 449 16 194 7.1 15 0.56 85 2.7 8.4 0.27 15 0.49 Incremental SU Lab Samples Maximum 1300 64 2.3 24 0.88 2.1 0.08 14 0.45 1.3 0.04 2.2 0.07 detected 95% UCL 527.6 29 1 10 0.38 1 0.04 6.6 0.21 0.6 0.02 1.1 0.04
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Cadmium Risk Evaluation: At the maximum detected cadmium concentration, the NOAEL- based HQ equals one for the short-tailed shrew. The LOAEL-based HQ did not exceed one for any wildlife receptor group. Thus, little or no population risk to wildlife is expected from exposure to cadmium in soil. Copper Risk Evaluation: At the maximum detected copper concentration, the NOAEL-based HQ exceeds one for the American woodcock (3.2) and the short-tailed shrew (1.8). The LOAEL- based HQ did not exceed one for these wildlife receptor groups (HQ = 0.37 for the woodcock; HQ = 0.14 for the shrew). At the 95% UCL concentration, the NOAEL-based HQ (1.5) exceeds 1 for the American woodcock but the LOAEL-based HQ did not exceed 1 for any wildlife receptor groups. Thus, little or no population risk to wildlife is expected from exposure to copper in soil. Lead Risk Evaluation: At the maximum IS lead concentration, the NOAEL-based HQs exceed 1 for all wildlife receptor groups. The LOAEL-based HQ slightly exceeds 1 only for the American woodcock (2.3). At the maximum XRF concentration, the NOAEL-based HQs exceed 1 for all wildlife receptor groups. The LOAEL-based HQs exceed one for all wildlife receptor groups except the meadow vole (0.84). At the 95% UCL IS concentration, the NOAEL-based HQs exceed 1 for the American woodcock (29), the mourning dove (10), and the short-tailed shrew (6.6). The LOAEL-based HQ does not exceed one for any receptor group. At the 95% UCL XRF concentration, the NOAEL-based HQs exceed one for all receptor groups. The LOAEL-based HQs exceed one for the American woodcock (16), the mourning dove (7.1), and the short-tailed shrew (2.7) indicating that there is potential for adverse impacts from lead on populations of ground-dwelling, insectivorous small mammals and birds, and herbivorous birds. The LOAEL-based HQs do not exceed one for any receptor group at the residential RSL of 400 mg/kg, indicating little or no population risk to wildlife is expected from exposure to lead in soil at this concentration. The adverse impacts on ecological receptors are expected to be limited due to the conservative nature of the SLERA. It is likely that the net effect of all the assumptions used in the SLERA yields a conservative estimate of total risk to ecological receptors. 2.7.2.5 Interpretation and Conclusions The ecological risk evaluation led to the following conclusions: There is no complete groundwater exposure pathway for ecological receptors. No explosives were positively detected in soil; therefore, no adverse impacts to ecological receptors exposed to explosives in soil are expected. Cadmium and copper were identified as a COPEC; little to no population risk to wildlife is expected for cadmium and copper in soil because LOAEL-based HQs were less than 1 for all wildlife receptor groups. Lead is the only contaminant of concern in soil. While there is potential for adverse impacts from lead on populations of ground-dwelling, insectivorous small mammals and birds, and herbivorous birds, adverse impacts on ecological receptors are expected to be overstated due to the conservative nature of the SLERA. Wildlife population adverse effects are not expected at the residential RSL of 400 mg/kg of lead.
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2.7.3 Basis for Taking Action It is the Army’s current judgment that the selected remedy identified in this ROD is necessary to protect public health or welfare from lead in soils. The basis for taking action is summarized in Table 2-8. A summary of the alternatives originally considered and evaluated in the RI/FS, along with more detailed information concerning the selected alternative for implementation, is presented in Section 2.9 and Section 2.12, respectively. The selected remedy supports the current and reasonably future land uses discussed in Section 2.6.
2.8 Remedial Action Objectives The Remedial Action Objectives (RAOs) consist of media-specific qualitative statements for protecting human health and the environment and/or meeting established regulatory requirements. The RAOs are based on a review of the MRS characterization data, ARARs, and other relevant information. Table 2-8 Basis for Taking Action Potential COC Receptor Media Exposure Requiring Basis for Taking Action Pathway Action Human Surface Direct Lead Lead concentrations pose risk to future Receptors Soils contact residential receptors, Post personnel and contractors, and construction workers/recreational users. Ecological Surface Direct Lead Lead is the only contaminant of concern in soil. Receptors Soils contact While there is potential for adverse impacts from lead on populations of ground-dwelling, insectivorous small mammals and birds, and herbivorous birds, adverse impacts on ecological receptors are expected to be overstated due to the conservative nature of the SLERA. Therefore, action is not required due to exposures to ecological receptors.
Human Groundwater Drinking Not Not Applicable Receptors water Applicable source Ecological Groundwater No pathway Not Not Applicable Receptors Applicable The RAOs were developed in the RI/FS based on criteria outlined in Section 300.430(e)(2)(i) of the NCP. RAOs specify the COCs, media of concern, exposure routes and receptors, and an acceptable contaminant level or range of levels for each exposure route. The RAOs for the SHSAR Impact Slope MRS are based on the following: COC: Lead; Media of Concern: Surface soil. The lead contamination was determined to be present from 0–6 inches bgs; and Exposure Routes and Receptors: The most probable receptors are recreational users or construction workers accessing the MRS on an occasional, short-term basis. Other potential receptors include Post personnel/authorized contractors, Fort Riley residents
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(e.g., children periodically playing on the slope), authorized contractors, and future construction workers. The primary exposure pathways include incidental ingestion of soil, dermal contact with soil, and inhalation of vapors and/or airborne dust released from soil. The USEPA Residential RSL of 400 mg/kg (which is the same as the KDHE Tier 2 Risk-Based Residential Standard) has been selected as the remediation goal (RG) for lead at the SHSAR Impact Slope MRS because this RSL is a level that is considered protective of the human health and environment for all human and ecological receptors of concern listed above and provides the basis for remediation at Fort Riley. Further, this RG provides for unrestricted reuse of the property. Therefore, the RAO for the MRS is to prevent ingestion/direct contact with lead in soil having concentrations in excess of 400 mg/kg.
2.9 Description of Alternatives The remedial alternatives evaluated for the SHSAR Impact Slope MRS as part of the detailed analysis of alternatives were presented in the RI/FS (Bay West, 2014a) and are summarized in Table 2-9. Table 2-9 Summary of Remedial Alternatives Evaluated for the MRS Alternative Alternative Cost and Estimated Timeframe Designation Description/Component Alternative 1 No action Estimated Capital Cost: $0 No Action Estimated Annual O&M Cost: $0 Estimated 30 Year Present Worth Cost (7% discount rate): $0 Estimated Construction Timeframe: No construction required (0 months) Estimated Time to Achieve RAOs: 30+ years Alternative 2 Public education Estimated Capital Cost: $108,500 LUCs Restriction on future land Estimated Annual O&M Cost: $75,000 use Estimated 30 Year Present Worth Cost (7% Physical access restrictions discount rate): $336,118 (fence) Estimated Construction Timeframe: 1 month Long-term Estimated Time to Achieve RAOs: 12 months monitoring/maintenance
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Table 2-9 Summary of Remedial Alternatives Evaluated for the MRS Alternative Alternative Cost and Estimated Timeframe Designation Description/Component Alternative 3 Excavation of 4,436.7 cubic Estimated Capital Cost: $3,750,022 Excavation and yards (6,650 tons) of lead- Estimated Annual O&M Cost: $0 Off-Site impacted soils Estimated 30 Year Present Worth Cost (7% Disposal Disposal of soils at a RCRA discount rate): $3,750,002 Subtitle C Landfill Estimated Construction Timeframe: 2 months Estimated Time to Achieve RAOs: 18 months Alternative 4 Placing soil cover as an Estimated Capital Cost: $1,813,791 Soil Cover access control to prevent Estimated Annual O&M Cost: $30,000 contact with contaminated Estimated 30 Year Present Worth Cost soils (7% discount rate): $2,044,089 Public education Estimated Construction Timeframe: 4 months Legal restriction on future Estimated Time to Achieve RAOs: 18 months land use Long-term monitoring/maintenance Yellow shading indicates the selected remedy. Alternative 1 was retained as a baseline against which to compare other alternatives as required by the NCP. Initial assessment of the remaining alternatives found that Alternatives 2, 3, and 4 would be effective, implementable, and cost effective, and thus were retained for further analysis. A description of each alternative is presented in the following subsections. 2.9.1 Alternative 1: No Action In accordance with the NCP, 40 Code of Federal Regulations (CFR) Section 300.430(e)(6), the No Action Alternative is evaluated as a baseline for comparison with other alternatives that provide a greater level of protection. The No Action Alternative equates with a determination to do nothing further at the MRS, and it can be selected only if investigation activities reveal that there is no remaining unacceptable health or environmental risks. The No Action Alternative is considered only to establish a “true” baseline risk during the RI/FS process. Actions that simply control future access to the MRS or limit exposures to existing contamination may not be considered when establishing the “true” baseline risk. Under this alternative, the SHSAR Impact Slope MRS would be left in its present condition with no institutional controls or further monitoring. 2.9.2 Alternative 2: LUCs Control measures that are administrative in nature can, in some situations, be as effective as remedial technologies in preventing human exposure to lead. Therefore, LUCs, which will include institutional controls (i.e., public health education and restriction on future land use) and engineering controls (i.e., physical access restrictions), are included in this alternative. The land use controls will be implemented by the Army. In addition, long-term monitoring/maintenance would be implemented to verify the LUCs were effective and whether lead was migrating either over land during rain events, etc., or downward through the soil to groundwater. This is not anticipated at this MRS as the lead is in the form of inorganic projectiles, principally pistol rounds, which were fired at targets set against the bluff. Additionally, the soils are bicarbonate soils that form a covering of lead carbonate on any free metal lead present. The lead carbonate is extremely insoluble with a solubility product of 1x10-13. Solubility of lead in groundwater is limited, and the water wells at the site are tested regularly and no lead is present. In addition,
W9128F-09-D-0059, TO 0009 2-26 January 2016 BWJ130451 Revision 03 Record of Decision Sherman Heights Small Arms Range Impact Slope Fort Riley, Kansas there is a ditch and berm area between the housing quarters and the slope base which provide a physical barrier to prevent soil from migrating down the slope. Further, the Sherman Heights area is a permanently grass-covered slope, which will alleviate the potential for soil to move downward toward the housing quarters. LUCs are developed to reduce or prevent exposure to contamination in soil and particulate matter and to protect the remedy where contamination exceeding screening criteria is left in place. Specific LUCs developed for the MRS would be documented as part of the remedial design in accordance with EPA-540-R-09-001 Institutional Controls: A Guide to Planning, Implementing, Maintaining, and Enforcing Institutional Controls at Contaminated Sites (USEPA, 2010b). Public Education Public education involves distribution of information about lead exposure to people in affected areas. Specific education activities that may prove effective at reducing exposures include holding public meetings with area stakeholders to inform the local community, and adding data to the facility information repository. Restrictions on Future Use Legal access restrictions include land use restrictions, which are incorporated into the Post-wide master plan. Use of this alternative requires compliance with the base’s LUC policy and USEPA or remedy review activities. Access restrictions would provide notification for any personnel entering the area that lead-contaminated soil exists in this area and excavation is restricted. Physical Access Restrictions Access restrictions can prevent contact with contaminated soil using physical barriers. For this alternative, fencing and signage would be required around the SHSAR Impact Slope MRS to restrict access and contact with lead-contaminated material. Long-Term Monitoring/Maintenance Annual inspection of the fence and signage is required. Soil sampling should be conducted every 2 years, and groundwater sampling should be conducted every 5 years, to verify that the lead is not migrating off-site. A LUC Implementation Plan will be drafted following completion of the ROD that will detail the specific sampling locations and frequencies. 2.9.3 Alternative 3: Excavation and Off-Site Disposal Excavation and off-site disposal of lead-contaminated soil with concentrations exceeding the RG removes the risk of exposure from the MRS in both residential and industrial user risk settings. At the SHSAR Impact Slope MRS, this would involve removing all soil contaminated with lead above the RG of 400 mg/kg. It is noted that the slope on which the material is present is approximately 30 degrees (i.e., a steep slope). The soils are shallow and underlain by lower permeability bedrock. The excavation of contaminated soils would have a very strong potential to destabilize the slope and cause slope failure with a landslide as a result. The volume of material requiring removal is estimated at approximately 6,650 tons. This was calculated using the assumptions that 5.5 acres (239,580 square ft) were contaminated to 0.5 ft bgs (i.e., 4,436.7 cubic yards) and assuming a density of 1.5 tons per cubic yard. Soil sampling following removal would be performed to confirm that the residual contamination is less than the RG. During excavation, dust monitoring and dust suppression is required to protect the workers and the public. In this alternative, all excavated soil is transported for disposal to a licensed RCRA Subtitle C landfill (Waste Management’s Rolling Meadows facility in Topeka, Kansas). The
W9128F-09-D-0059, TO 0009 2-27 January 2016 BWJ130451 Revision 03 Record of Decision Sherman Heights Small Arms Range Impact Slope Fort Riley, Kansas remaining exposed bedrock slope would be covered with topsoil, native prairie grass, and reinforced rollout material for erosion prevention. 2.9.4 Alternative 4: Soil Cover This alternative entails using a soil cover as an access control to prevent contact with contaminated soils. In addition, the other LUCs described in Alternative 2 will be required, with the exception that a fence is not required, and access restrictions and long-term monitoring/ maintenance requirements will vary. Long-Term Monitoring/Maintenance Annual inspections will be required to verify that the cover material remains in place. If the inspections show that there is potential for lead-contaminated soil to be exposed, cover maintenance will be required. In addition, soil verification sampling should be conducted every two years and groundwater verification should be conducted every five years, for additional verification of cover integrity.
2.10 Comparative Analysis of Alternatives In accordance with the NCP, the alternatives for the SHSAR Impact Slope MRS were evaluated using the nine criteria described in Section 121(a) and (b) of CERCLA and 40 CFR Section 300.430 (e)(9)(iii) as cited in NCP Section 300.430(f)(1)(i). These criteria are classified as threshold criteria, balancing criteria, and modifying criteria. Threshold criteria are standards that an alternative must meet to be eligible for selection as a remedial action. There is little flexibility in meeting the threshold criteria—the alternative must meet them or it is unacceptable. The following are classified as threshold criteria: Overall protection of human health and the environment; and Compliance with, or an applicable waiver of, ARARs. Balancing criteria weigh the tradeoffs between alternatives. These criteria represent the standards upon which the detailed evaluation and comparative analysis of alternatives are based. In general, a high rating on one criterion can offset a low rating on another balancing criterion. Five of the nine criteria are considered balancing criteria: Long-term effectiveness and permanence; Reduction of toxicity, mobility, and volume through treatment; Short-term effectiveness; Implementability; and Cost. Modifying criteria that may be considered to the extent that information is available during the RI/FS, but can be only fully considered after public and regulator comments have been received: Community acceptance; and Regulatory acceptance. This section summarizes how well each alternative satisfies each evaluation criterion and indicates how it compares to the other alternatives under consideration. A relative ranking of alternatives against the nine criteria is shown in Table 2-10.
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Table 2-10 Summary of Comparative Analysis of Alternatives
Alternatives CERCLA Criteria Alternative 1: No Alternative 2: Alternative 3: Alternative 4: Action LUCs Excavation and Soil Cover Off-Site Disposal Threshold Criteria Overall Protection of Human Does not meet Meets criterion Meets criterion Meets criterion Health and the Environment criterion Does not meet Compliance with ARARs1 Meets criterion Meets criterion Meets criterion criterion Primary Balancing Criteria Long-Term Effectiveness and Permanence Reduction of Toxicity, Mobility, or Volume through Treatment2 Short-Term Effectiveness Implementability Cost $0 $336,118 $3,750,022 $2,044,089 Modifying Criteria Regulatory Acceptance Community Acceptance NC NC NC NC Ranking: High Moderate Low 1 There are no location or chemical-specific ARARs. However, the RAO is to prevent exposure to lead in soil having concentrations in excess of the RG of 400 mg/kg. Alternative 1 would not meet the RAO. Alternatives 2, 3, and 4 would meet the RAO. 2 No treatment is performed in any of the four alternatives. Therefore, no reduction in toxicity or volume is provided. However, a reduction in mobility is provided by Alternatives 3 and 4, so they were scored “moderate.” NC = No comments were received from stakeholders or community members. Yellow shading indicates the selected remedy. 2.10.1 Overall Protection of Human Health and the Environment Overall protection of human health and the environment addresses whether each alternative provides adequate protection of human health and the environment and describes how risks posed through each exposure pathway are eliminated, reduced, or controlled through treatment, engineering controls, and/or institutional controls. Lead is limited to the MRS boundary and migration of lead from the MRS is not anticipated, as the lead is in the form of inorganic projectiles, principally pistol rounds, which were fired at targets set against the bluff. Additionally, the soils are bicarbonate soils that form a covering of lead carbonate on any free metal lead present. The lead carbonate is extremely insoluble with a solubility product of 1x10-13. Solubility of lead in groundwater is limited, and the water wells at the site are tested regularly and no lead is present. Alternative 1 provides no effect on the MRS; therefore, it does not address any of the identified risks to human health and the environment. Alternative 2 provides protection to the general public by limiting access to the MRS to which the elevated lead concentrations are limited. Alternative 2 further provides protection for authorized personnel entering the MRS by requiring LUCs that notify personnel of the potential hazards and ensure personal protective equipment (PPE) is utilized during any intrusive work at the MRS. However, Alternative 2 requires long-term management to maintain and enforce LUCs. Alternative 3 would provide adequate protection of human health and the environment
W9128F-09-D-0059, TO 0009 2-29 January 2016 BWJ130451 Revision 03 Record of Decision Sherman Heights Small Arms Range Impact Slope Fort Riley, Kansas through source removal. Therefore, the highest level of protection to human health and the environment would be provided by this alternative. Alternative 4 provides effective protection of human health and the environment as a cover is installed over lead concentrations exceeding the RG; however, long-term maintenance of the cover is required and erosion control may prove to be difficult. 2.10.2 Compliance with Applicable or Relevant and Appropriate Requirements Section 121(d) of CERCLA and NCP Section 300.430(f)(1)(ii)(B) require that remedial actions at CERCLA sites attain legally applicable or relevant and appropriate Federal and State requirements, standards, criteria, and limitations, which are collectively referred to as “ARARs,” unless such ARARs are waived under CERCLA Section 121(d)(4). Compliance with ARARs evaluates whether the alternative meets Federal and State environmental statutes, regulations, and other requirements that pertain to the MRS, or whether a waiver is justified. Action-specific, location-specific, and chemical-specific ARARs do not apply to Alternatives 1 or 3. However, lead concentrations exceed the RGs; leaving this soil in place without further protection would not comply with the RAO. As all soil with lead above the RG would be removed under Alternative 3, the RAO is met. For Alternative 2 and 4, the action-specific ARARs (i.e., the Environmental Use Controls located in K.S.A. 65-1, 228(b) and K.S.A. 65-1, 230(a)) apply and would be met by these alternatives. There are no location-specific or chemical-specific ARARs for Alternatives 2 or 3. However, these alternatives meet the RAO which is to prevent exposure to lead in soil having concentrations in excess of the RG of 400 mg/kg by implementing land use controls and/or access restrictions on the property. A summary of site-specific ARARs is provided in Table 2-11. Table 2-11 Summary of Site-Specific ARARs Chemical-Specific ARARs and To Be Considered Guidance Regulation/Citation Description Rationale USEPA screening levels for To be considered guidance for USEPA Residential RSLs residential exposure based on soil 1x10-6 risk or hazard index of 1.0 Action-Specific ARARs Environmental Use Controls A legal mechanism for applying Used to provide landowners with (K.S.A. 65-1, 228(b) and K.S.A. restrictions, prohibitions, and a way to achieve site closure by 65-1, 230(a)) conditions on land use for a addressing environmental property with contaminant concerns caused by concentrations that exceed contamination. Applicable to residential standards alternatives where land use controls are part of the remedy.
2.10.3 Long-Term Effectiveness and Permanence Long-term effectiveness and permanence refers to expected residual risk and the ability of a remedy to maintain reliable protection of human health and the environment over time, once cleanup levels have been met. This criterion includes the consideration of residual risk that will remain on-site following remediation and the adequacy and reliability of controls. Alternative 1 does not provide long-term effectiveness or permanence for the protection of public health and the environment. Alternative 2 and 3 provide reasonably effective long-term
W9128F-09-D-0059, TO 0009 2-30 January 2016 BWJ130451 Revision 03 Record of Decision Sherman Heights Small Arms Range Impact Slope Fort Riley, Kansas protection; however, long-term maintenance of the LUCs and/or soil cover are required. Therefore, these alternatives provide effectiveness but not permanence. The fence would provide protection of the general public, who could no longer directly access the contaminated area. Further, there is a ditch and berm area between the housing quarters and the slope base. The Sherman Heights area is a permanently grass-covered slope, which will alleviate the potential for soil to move downward toward the housing quarters. For Alternatives 3 and 4, erosion control may prove to be difficult due to the slopes present. Alternative 3 provides long- term effectiveness and permanence because soil with lead concentrations exceeding the RGs will be removed and sequestered in a permitted RCRA Subtitle C landfill. 2.10.4 Reduction of Toxicity, Mobility, or Volume Through Treatment Reduction of toxicity, mobility, or volume through treatment refers to the anticipated performance of the treatment technologies that may be included as part of a remedy. No treatment of lead contaminated soils was evaluated. Therefore, no reduction in toxicity, mobility or volume through treatment is provided. However, the monitoring performed under Alternative 2 would ensure that migration of lead from the MRS was not occurring, and additional action may be taken if it is identified. Alternative 3 would effectively reduce mobility of lead-contaminated material by sequestration in a permitted RCRA Subtitle C landfill. The toxicity and volume of the waste would remain the same for material removed from the MRS; however, the risk of exposure to lead-contaminated soil with concentrations exceeding the RG would be eliminated. Alternative 4 does not reduce toxicity or volume of contaminants, since the contaminants would remain at the MRS; however, the mobility of the contaminants would be reduced by the cover. 2.10.5 Short-Term Effectiveness Short-term effectiveness addresses the period of time needed to implement the remedy and any adverse impacts that may be posed to workers, the community, and the environment during construction and operation of the remedy until cleanup levels are achieved. Alternative 1 has no action associated with it; therefore, it provides no short-term measures to prevent impact to human or environmental receptors so is effective in the short-term. The primary physical remedial action associated with Alternative 2 is fencing installation. No contact with contaminants would occur during construction of the fence. Therefore, no short-term risks to workers or the community are associated with Alternative 2. Lead-contaminated dust will be generated during the excavation activities in Alternative 3. This potential exposure would be mitigated by the use of PPE, dust monitoring and suppression measures during the remedial actions. Additionally, disturbance of nearby residents (e.g., noise, truck traffic, etc.) significantly increases during the Alternative 3 remedial actions. For Alternative 4, some lead-contaminated dust may be generated during the cover installation; however, it would be less dust than Alternative 3. Disturbance of nearby residents (e.g., noise, truck traffic, etc.) significantly increases during the remedial actions. 2.10.6 Implementability Implementability addresses the technical and administrative feasibility of a remedy from design through construction and operation. Factors such as availability of services and materials, administrative feasibility, and coordination with other governmental entities are also considered. No activities are proposed under Alternative 1; therefore, this alternative would be technically and administratively feasible. The implementation history of the existing LUCs contained in both Alternatives 2 and 4 have been shown to be technically and administratively feasible. LUCs have been implemented at this facility and Geographical Information System (GIS) technology
W9128F-09-D-0059, TO 0009 2-31 January 2016 BWJ130451 Revision 03 Record of Decision Sherman Heights Small Arms Range Impact Slope Fort Riley, Kansas exists to maintain the facility specific LUC database. Personnel and materials required for the fence construction in Alternative 2 are readily available. Alternative 3 uses proven, tested technologies that are technically feasible from an engineering perspective. Soil wetting and dust control would be required to protect workers and nearby residents. Noise and traffic disruption impacts on nearby residents during daylight hours will increase during the remedial action but can be mitigated with proactive planning actions. However, there would be design challenges implementing the action due to the slope present and as the soils are shallow and underlain by lower permeability bedrock. Per Occupational Safety and Health Administration (OSHA) 1926 Subpart P, Excavations, the sandy soil and steep sloping (greater than 1.5:1) may require shoring, or other engineering controls, to provide slope stability during the implementation of the remedial action. The slope of the SHSAR Impact Slope MRS will cause excavation to proceed slower than excavation on less steep slopes and may require specialized equipment, particularly in areas of shallow bedrock; however, the work can still be implemented. Engineering analysis in areas, in particular those areas without shallow bedrock, is required to assess the potential for localized slope failure. The excavation of contaminated soils would have a very strong potential to destabilize the slope and cause slope failure with a landslide as a result. Re-vegetation, erosion control, stabilization, and/or engineering controls may be required in these areas to address slope failure potential if it exists. Alternative 4 is implementable. All services and materials required for the implementation of this alternative are available for use. As previously stated, the slope of the SHSAR Impact Slope MRS could represent a threat to future cover integrity; frequent cover maintenance would likely be required. Further, the slope of the SHSAR Impact Slope MRS will cause challenges to implementing this remedy and may require specialized equipment, particularly in areas of shallow bedrock; however, the work can still be implemented. Engineering analysis in areas, in particular those areas without shallow bedrock, is required to assess the potential for localized slope failure. Re-vegetation, erosion control, stabilization, and/or engineering controls may be required in these areas to address slope failure potential if it exists. The slope will also cause an increase of the maintenance requirements for the cover beyond what would typically be expected. 2.10.7 Cost Total costs are summarized in Table 2-12. Relative to each other, Alternative 1 has no costs, and Alternative 2 has low overall costs. Alternatives 3 and 4 are significantly more expensive than Alternative 2, where Alternative 3 is the most costly.
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Table 2-12 Cost Estimate Summary for the Selected Remedy Fort Riley SHSAR, Kansas
Alternative 2 COST ESTIMATE SUMMARY Land Use Controls Site: Sherman Heights Small Arms Range (SHSAR) Impact Slope MRS Location: Fort Riley, Kansas Phase: RI/FS Base Year: 2013 Capital Costs UNIT Description QTY UNIT COST TOTAL NOTES Institutional Controls Public meeting, Admin Record Update 1 LS $ 5,000 $ 5,000 Develop a WP and survey the IC area Master Plan Input 1 LS $ 2,000 $ 2,000 Update Post - w ide planning
Fencing 4,000 lin ft $ 20.00 $ 80,000.00 Kansas Fencing estimate
Project Contingency 25% $ 20,000 Program Management 15% $ 1,050 does not include fencing TOTAL CAPITAL COST $ 108,050 Annual Operation and Maintenance (O&M) Costs UNIT Description QTY UNIT COST TOTAL NOTES Annual Fence Maintenance 30 EA $ 2,000 $ 60,000 Annual Program Maintenance 30 EA $ 500 $ 15,000 SUBTOTAL $ 75,000 TOTAL ANNUAL COST $ 75,000 Periodic Costs UNIT Description QTY UNIT COST TOTAL NOTES Five Year Review 6 EA $ 500 $ 3,000 Update every 5 years for 30 years 2-year Soil Sampling 15 EA $ 12,650 $ 189,750 Every tw o years for 30 years 5-year Groundw ater Sampling 6 EA $ 17,659 $ 105,956 Every five years for 30 years
TOTAL PERIODIC COST $ 298,706 Total Present Worth Cost: $ 336,118
2.10.8 Regulatory Acceptance Note that the Army is the lead agency and the USEPA is the lead regulatory agency with support from KDHE for the SHSAR Impact Slope MRS. The USEPA and KDHE have expressed their support for Alternative 2. The USEPA and KDHE have expressed their support for Alternative 2. (See the USEPA and KDHE letters in Attachment 1.) 2.10.9 Community Acceptance During the public comment period and public meeting, one comment from the public was received. The comment was on the design of the fence and was addressed by Fort Riley during the public meeting. No other concerns related to the selected remedy were voiced. Therefore, the community accepts the selected remedy as specified in the Proposed Plan.
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2.11 Principal Threat Wastes The NCP states a preference for using (to the extent practicable) treatment that reduces the toxicity, mobility, or volume of the principal threat wastes. The principal threat concept refers to the source materials at a CERCLA site considered to be highly toxic or highly mobile that generally cannot be reliably controlled in place or present a significant risk to human health or the environment should exposure occur. Lead is not considered to be a principal threat waste as migration of lead from the MRS is not occurring nor is it anticipated and a fence will effectively prevent human contact with the soils, eliminating threats to human health. Therefore, the cost and implementation issues associated with treatment, as described under Alternative 3, at the MRS are not justified.
2.12 Selected Remedy The selected remedy for the SHSAR Impact Slope MRS, Alternative 2 (LUCs), described in Section 2.9.3, was selected because it provides a long-term, cost-effective, implementable solution to address the lead contaminated surface and subsurface soils at the MRS. This section describes the rationale for choosing the selected remedy (Section 2.12.1), provides specific details and costs for the selected remedy (Section 2.12.2), and describes the expected outcomes after the selected remedy is implemented (Section 2.12.3). The Army is responsible for implementing, maintaining, monitoring, and enforcing the remedial actions for the duration of the remedy selected in this ROD. The Army will exercise their responsibility in accordance with CERCLA and the NCP. 2.12.1 Summary of the Rationale for the Selected Remedy Selection of Alternative 2 as the selected remedy is based on the detailed analysis of remedial alternatives presented in the RI/FS (Bay West, 2014a). The Army, USEPA, and KDHE believe the selected remedy meets the threshold criteria and provides the best balance of tradeoffs among the other alternatives with respect to the balancing and modifying criteria. The selected remedy is technically feasible, implementable, and cost effective. The selected remedy meets the RAO by mitigating potential risks associated with residential receptors, commercial/industrial receptors, and recreational/construction worker receptors direct contact with lead in soils. The Army believes that the selected remedy can be easily implemented based on the implementation history of the LUCs contained in the selected remedy. These LUCs have been shown to be technically and administratively feasible. The selected remedy will be compliant with ARARs. 2.12.2 Summary of Estimated Remedy Costs A detailed, activity-based breakdown of the estimated costs associated with implementing and maintaining the selected remedy are summarized in Table 2-12. The information in the cost estimate summary tables is based the best available information regarding the anticipated scope of the selected remedy. Changes in the cost elements may occur as a result of new information and data collected during the implementation of the selected remedy. Significant changes will be documented in the form of a memorandum in the Administrative Record file, an Explanation of Significant Differences (ESD), or a ROD Amendment, as appropriate. This is an order-of-magnitude engineering cost estimate that is expected to be within +50% to -30% of the actual project cost.
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2.12.3 Expected Outcomes of Selected Remedy The expected outcomes of the selected remedy are: Mitigation of potential risks associated with lead in surface soils through implementation of LUCs; No limits on the use of groundwater because there are no adverse impacts to groundwater associated with the military munitions use of the property; and The current and reasonably anticipated future land uses will be supported and will not represent unacceptable risks to receptors. UU/UE of the MRS will not be achieved. LUCs will be required indefinitely or until such time as it is determined that contamination levels are below the RG of 400 mg/kg. The LUCs will be administered in accordance with the requirements of the LUC Plan.
2.13 Statutory Determinations Under CERCLA Section 121 and NCP Section 300.430(f)(5)(ii), the lead agency must select a remedy that protects human health and the environment, complies with ARARs (unless a waiver is justified), is cost-effective, and uses permanent solutions and alternative treatment technologies or resource recovery technologies to the maximum extent practicable. In addition, CERCLA also includes: 1) a preference for remedies that employ treatment which permanently and significantly reduces the volume, toxicity, or mobility of hazardous wastes; and 2) a bias against off-site disposal of untreated wastes. Periodic 5-year reviews are required if the remedy will result in hazardous substances remaining in place above levels allowing for UU/UE. The following sections discuss how the selected remedy meets these statutory requirements. 2.13.1 Protection of Human Health and the Environment The selected remedy, Alternative 2: LUCs will protect human health by mitigating contact with lead contamination in surface soils. No hazards or risks to the environment are present at the SHSAR Impact Area MRS. 2.13.2 Compliance with ARARs As discussed in Section 2.10.2, remedial actions must comply with both Federal and State ARARs. No chemical- or location-specific ARARs were identified for the selected remedy. However, this alternative does meet the RAO which is to prevent exposure to lead in soil having concentrations in excess of the RG of 400 mg/kg by implementing land use controls on the property. Table 2-11 summarizes the action-specific ARARs for the selected remedy. The selected remedy will comply with the action-specific ARARs that were identified. 2.13.3 Cost Effectiveness In the Army’s judgment, the selected remedy is cost-effective and represents a reasonable value for the money to be spent. In making this determination, the following definition was used: “A remedy shall be cost-effective if its costs are proportional to its overall effectiveness” (40 CFR 300.430[f][1][ii][D]). Overall effectiveness was evaluated by assessing three of the five balancing criteria in combination: long-term effectiveness and permanence; reduction in toxicity, mobility, and volume through treatment; and short-term effectiveness. Overall effectiveness was then compared to costs to determine cost-effectiveness. The relationship of the overall effectiveness of the selected remedy was determined to be proportional to its costs. Therefore, the selected remedy represents a reasonable value for the money to be spent. The estimated present worth cost of the selected remedy (in 2014 dollars) is $336,118.
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2.13.4 Utilization of Permanent Solutions and Alternative Treatment Technologies to the Maximum Extent Practicable The Army has determined that the selected remedy represents the maximum extent to which permanent solutions and treatment technologies can be utilized in a practicable manner at the MRS. As compared to Alternatives 3 and 4, the Army has determined that the selected remedy provides the best balance of trade-offs in terms of the five balancing criteria, while also considering the statutory preference for treatment and bias against off-site treatment and disposal and considering regulatory and community acceptance. The NCP recognizes that some contamination problems will not be suitable for treatment and permanent remedies. For this MRS, there is no permanent treatment to be employed. The selected remedy for the SHSAR Impact Slope MRS addresses lead contaminated surface soils. The selected remedy satisfies the criterion for long-term effectiveness by implementing LUCs that have are anticipated to be effective and reliable. The selected remedy presents lower short-term risks than Alternatives 3 and 4. Further, the selected remedy does not present implementation issues associated with Alternatives 3 and 4. While the selected remedy does not provide a permanent solution, risks associated with lead in soil will be mitigated. LUCs will be required indefinitely or until such a time as it is determined that there are no residual hazards present. Alternative treatment technologies were not applicable to the MRS. 2.13.5 Preference for Treatment as a Principal Element The NCP establishes the expectation that treatment will be used wherever practicable (40 CFR 300.430[a][1][iii](A]). The selected remedy for the SHSAR Impact Slope MRS does not satisfy the statutory preference for treatment. However, lead is not considered to be a principal threat waste as migration of lead from the MRS is not occurring and will be continued to be monitored via media sampling, and a fence will prevent human contact with soils, eliminating threats to human health. Therefore, treatment technologies for lead in soil were not recommended due to the steep slopes present, making excavation of soils difficult. Any risks can be reliably controlled using LUCs. 2.13.6 Five-Year Review Requirements It is expected that lead will remain in the surface soils at the SHSAR Impact Slope MRS once the selected remedy is implemented. As a result, UU/UE will not be attained at the MRS. Therefore, a statutory review will be conducted within 5 years after initiation of remedial action to ensure that the remedy is, or will be, protective of human health and the environment.
2.14 Documentation of Significant Changes The Proposed Plan for the MRS was released for public comment on 15 November 2014. The PP identified Alternative 2: LUCs as the Preferred Alternative. The public did not provide comments on the PP that lead to a change in the selected remedy. Thus, it was determined that no significant changes to the Preferred Alternative, as originally identified in the PP, were necessary or appropriate.
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3.0 RESPONSIVENESS SUMMARY
This section provides a summary of the public comments regarding the Proposed Plan for the remedial action at the SHSAR Impact Slope MRS, Fort Riley, and the Army response to comments. At the time of the public review period, the Army had selected Alternative 2, LUCs, as the preferred alternative for the MRS. No written comments were received during the public comment period. A public meeting was held on 1 December 2014. One comment from the public was received during the public meeting as discussed in Section 3.2. This comment did not result in a change to the selected remedy.
3.1 Stakeholder Comments and Lead Agency Responses As noted previously, this document is issued by the Army, the lead agency for the SHSAR Impact Slope MRS. The Army has consulted with the USEPA and KDHE, and they concur with the selected remedy. The USEPA and KDHE provided comments on a Draft Final ROD that were incorporated into the Final ROD as shown in Attachment 4. The USEPA and KDHE accepted all changes and indicated that they had no further comments on the ROD.
3.2 Community Participation The RI/FS and Proposed Plan for the MRS were made available to the public on 15 November 2014. The availability of these documents was published in the 15 November 2014, in the Junction City Daily Union News, Junction City, Kansas, and on 18 November 2014 in the Manhattan Mercury, Manhattan, Kansas (Attachment 2) with a 30 day public comment period from 15 November 2014 through 16 December 2014. In addition, the Army held a public meeting on the Proposed Plan on 1 December 2014 at Fort Riley’s Conference Center, 446 Seitz Drive, Fort Riley, Kansas, to accept oral and written comments. The meeting was transcribed. A copy of the transcript is included as Attachment 3.
3.1 Summary of Comments Received during the Public Comment Period and Agency Responses Comments received during the public comment period on the Proposed Plan are summarized below. The comments are categorized by source. 3.1.1 Comments Received During the Public Meeting One comment specific to the preferred alternative was received during the public meeting held on 1 December 2014. The comment received on the preferred alternative is summarized as follows: Comment 1: It was requested that Fort Riley consider the aesthetic effects when selecting the fence. Pictures were taken with the hill as background. A fence would negatively impact the view. It was also noted that signs and fences do not prevent kids from entering an area. Fort Riley Response: Fort Riley, the USEPA, and KDHE have not discussed the specific design or location of the fence. That determination is part of the Remedial Design. The Army will strive to not have the fence negatively impact the view. Input will be gathered from the USEPA and KDHE and the final design of the fence will be approved by the USEPA.
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3.1.2 Written Comments Received During the Comment Period There were no written comments received during the comment period on the Proposed Plan.
3.3 Technical and Legal Issues No technical or legal issues regarding the Proposed Plan were identified during the public comment period. This ROD will be added to the Administrative Record file after it is signed. In addition, a notice of the availability of the ROD will be published in the two local newspapers, the Daily Union News, Junction City, Kansas, in accordance with NCP Section 300.430(f)(6): “After the [ROD] is signed, the lead agency shall: (i) Publish a notice of the availability of the [ROD] in a major local newspaper of general circulation; and (ii) Make the [ROD] available for public inspection and copying at or near the facility at issue prior to the commencement of any remedial action.”
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4.0 REFERENCES
Bay West, 2014a. Remedial Investigation/Feasibility Study, Sherman Heights Small Arms Range Impact Slope Munitions Response Site, Fort Riley, Junction City, Kansas. Prepared for the U.S. Army Corps of Engineers, Omaha District. February. Bay West, 2014b. Proposed Plan. Prepared for the U.S. Army Corps of Engineers, Omaha District. August. Burns and McDonnell, 2001. Draft Final Remedial Investigation Report for the Former Fire Training Area, Marshall Army Airfield at Fort Riley, Kansas. March 26, 2001. DODM 4715.20, Defense Environmental Restoration Program (DERP) Management (March 9, 2012) Engineering Environmental Management, Inc. (e²M), 2005. Stakeholder Final of the Military Munitions Response Program, Historical Records Review, Fort Riley, Kansas. April 2005. e2M, 2006. Site Inspection Report, Fort Riley, Kansas. June 2006. Fort Riley, 2010. Integrated Natural Resources Management Plan (INRMP). Environmental Division, Directorate of Public Works. April 13, 2010. Kansas Department of Health and Environment (KDHE), 2010. Risk-Based Standards for Kansas RSK Manual, 5th Version. Bureau of Environmental Remediation. October 2010. Retrieved from http://www.kdheks.gov/remedial/download/RSK_Manual_10.pdf OHM Corporation, August 1994. X-Ray Fluorescence (XRF) Survey and Confirmatory Sampling. U.S. Environmental Protection Agency (USEPA), 1989. Risk Assessment Guidance for Superfund, Volume I, Human Health Evaluation Manual (Part A). USEPA Office of Emergency and Remedial Response. Interim Final. USEPA/540/1-89/002. December. USEPA, 1991. Risk Assessment Guidance for Superfund, Volume I – Human Health Evaluation Manual Supplemental Guidance, “Standard Default Exposure Factors.” Interim Final. OSWER Directive 9285.6-03. USEPA, 1999. Guide to Preparing Superfund Proposed Plans, Records of Decision, and Other Remedy Selection Decision Documents. Washington D.C. November 1999. EPA/540-R-98- 031. USEPA, 2005a. Guidance for Developing Ecological Soil Screening Levels. OSWER Directive 9285-7.755 Office of Solid Waste and Emergency Response. Washington D.C. November 2003. Revised February 2005. USEPA, 2005b. Ecological Soil Screening Levels for Lead. Interim Final. OSWER Directive 9285-7.70. Office of Solid Waste and Emergency Response. Washington D.C. March 2005. USEPA, 2005c. Ecological Soil Screening Level For Cadmium. Interim Final. OSWER Directive 9285.7-65. March 2005. USEPA, 2007. Ecological Soil Screening Level for Copper. Interim Final. Office of Solid Waste and Emergency Response. OSWER Directive 9285.7-71. April 2007.
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Record of Decision Sherman Heights Small Arms Range Impact Slope Fort Riley, Kansas
USEPA, 2009. Update of Adult Lead Methodology’s Default Baseline Blood Lead Concentration and Geometric Standard Deviation Parameters. OSWER 9200.2-82. June 2009. Retrieved from http://www.epa.gov/superfund/lead/products/almupdate.pdf USEPA, 2010a. ProUCL, Version 4.1.00. Statistical Software for Environmental Applications for Data Sets with and without Nondetect Observations. Retrieved from http://www.EPA.gov/osp/hstl/tsc/software.htm USEPA, 2010b. Institutional Controls: A Guide to Planning, Implementing, Maintaining, and Enforcing Institutional Controls at Contaminated Sites. Interim Final. EPA-540-R-09-001. November. USEPA, 2011a. Toolkit for Preparing CERCLA Records of Decision. Washington, D.C. September 2011 USEPA, 2011b. Frequent Questions from Risk Assessors on the Adult Lead Methodology (ALM). September 19, 2011. USEPA, 2012a. Information for Risk Assessors. March 2012. Retrieved from http://www.EPA.gov/superfund/lead/pbrisk.htm USEPA, 2012b. Ecological Soil Screening Level (ECO-SSL) Guidance and Documents. Accessed February 22. Retrieved from http://www.EPA.gov/oswer/riskassessment/ecorisk/ecossl.htm USEPA, 2013. Regional Screening Table User’s Guide. May 2013). Retrieved from http://www.EPA.gov/reg3hwmd/risk/human/rb-concentration_table/usersguide.htm
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Record of Decision Sherman Heights Small Arms Range Impact Slope Fort Riley, Kansas
Attachment 1
USEPA and KDHE Letters of Concurrence
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Record of Decision Sherman Heights Small Arms Range Impact Slope Fort Riley, Kansas
Attachment 2
Public Notice Proofs
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Record of Decision Sherman Heights Small Arms Range Impact Slope Fort Riley, Kansas
Attachment 3
Transcripts from Public Meeting
W9128F-09-D-0059, TO 0009 January 2016 BWJ130451 Revision 03 Good evening everyone…My name is Craig Phillips and I’m the Chief of the Pollution Prevention and Cleanup Branch of the Environmental Division, Directorate of Public Works.
Among the programs I oversee is the Installation Restoration Program which addresses the cleanup of areas impacted by past practices.
Tonight we’re here to share information and gain your feedback on a proposed plan to address one of those areas.
Before we proceed, I’d like to introduce the installation staff that are here in an official capacity: ‐ COL Cole ‐ Tim ‐ Jeff ‐Herb ‐ My IRP team of Dick, Andrea and John = who is project manager for this site ‐ Corps… ‐ Bay West… ‐ Our partners, Travis Daneke from KDHE and Amar Safadi from the EPA
Next slide please I will go into much more detail about the site later, but first, I want to make clear why we’re here tonight.
Our purpose for this public meeting is to inform the public of the risks associated with the former Sherman Heights Small Arms Range site and our plan to come as close to eliminating those risks as we reasonably can.
Federal regulations require us to hold meetings at certain points in the cleanup process. Today’s meeting includes members of our Restoration Advisory Board, a civilian board that provides the Army with feedback throughout the process.
RAB Members here tonight are Chuck Otte and Florence Whitebread
We want to inform you, but also hear from you, tonight. Your feedback and questions are welcomed. The area north of Colyer Manor, with the steep hillside that serves as a natural backstop, has likely been a range area since the first Soldiers arrived on Fort Riley and started training.
Formal use peaked during war time and ended after the Vietnam War.
Investigations began in earnest in 2005 when the Army began completing cleanup of contamination left from industrial processes such as dry cleaning operations and vehicle maintenance shifted to munitions and their constituents
Two investigations found metal munitions debris, called MD, and munitions items that had failed to function, referred to as Munitions and Explosives of Concern, or MEC.
All MEC found was removed from the site, as was much of the MD
Lead, shot into the hillside, remains in the soil
Risks from MD, MEC and lead were all analyzed The first risk factor we’ll talk about is MEC, or munitions and explosives of concern.
It can also be referred to as UXO or unexploded ordnance,
MEC are items that are potentially explosive, although most found are old and degraded and unlikely to remain explosive.
MEC found included a Civil War era Hotchkiss 3” projectile; a 3 inch common projectile from the Spanish‐American War era; and a 2.36 inch bazooka round from the WWII/Korean War era
All “anomalies” were dug up and any suspected MEC items were detonated in the Impact Area
Munitions debris (MD) is more commonly found during investigations is munitions debris. MD can be spent shell casings, fired projectiles, or expended ordnance items, they are not explosive
MD included expended munitions items to include; 2 –2.36 bazooka rounds, 16 Stokes Practice mortars, a hand grenade, a practice grenade, smoke/illumination grenades, and flares.
In the two investigations at SHSAR, most of what was removed was metal debris not related to munitions –fence posts, wire, etc. that made up the nearly 3 tons removed. This map shows, as colored squares, where the MD was concentrated
The black dot indicates the location of the Stokes Mortars
Red dots indicate the location of the Hotchkiss and 3” common projectiles, and the 2.36 inch bazooka round The second risk factor at which we looked was lead in the soil
Shooting small arms rounds at the ranges put a lot of lead projectiles into the soil on the hillside
Soil samples have ranged from as low as 67 parts per million to as much as 38,000 parts per million, although only two samples even came close to the high end of that range.
For reference, one part per million is roughly 1 drop of water in 13 gallons of water. PPM is equal to milligrams per kilogram
KDHE standards for lead in soils for residential areas is 400 ppm. Because we have levels in soil that exceed that standard, some action to reduce exposure to that lead is warranted. This map shows the locations of the lead sampling in blue.
In 2011, 155 soil samples were taken
Of those, only 44 detected lead, and only 30 samples detected lead above the KDHE residential standard
All of those samples came from within the red area, corresponding with the location of the old anti‐tank range which was a sub‐caliber range The final risk we assessed was lead in water
Because our soils are derived from limestone, which is mostly calcium carbonate, free lead in soil is very quickly coated by a thin layer of lead carbonate, which limits how much is dissolved into groundwater
Lead piping for use in drinking water has been outlawed for over 20 years, so that historical source of lead contamination is drinking water is highly unlikely
Our well field does lie to the south and east of the SHSAR area, but all groundwater samples taken during the investigation were negative –what we call non‐detect –for lead Our water program staff regularly samples our drinking water at the plant and in randomly selected residences when residents allow us access. NO samples at Colyer Manor have ever detected lead. The last drinking water samples were collected in September 20141 at housing units 3006‐5, 3020‐4, 3053‐8, and 3142‐2.
Therefore, no health risks are evident for groundwater consumption Here are the locations of groundwater sampling done as part of the investigation
Note that some locations groundwater could not be located, likely because those samples were taken farther up the slope where groundwater isn’t found. So, what is the plan?
Lead in soil is the only unacceptable risk remaining at the site due to concentrations above 400 ppm
We considered four actions, called “remedies” in the cleanup process
The first –No Action – doesn’t mitigate the risk and serves only as a baseline
Alternative 2 involves what are known as Land Use Controls, essentially a fence and signs warning people to keep out. Estimated cost of this option is roughly $350,000, possibly more, depending on the extent of the fence
Alternative 3 would involve digging up much of the base of the hill and having it disposed of off the installation. This is estimated to cost over $3.7 million, and would likely leave the base of the hill rather unstable. Additional work might be required to stabilize the base
Alternative 4 would cover the contaminated soil with one or more feet of clean soil to reduce exposure. That option is estimated to cost over $2 million Based on effectiveness and cost, the preferred remedy is option 2 –fencing and signage.
After the fence installation there would be annual inspections to look for and fix damage to the fence or signs ,
Soil sampling every two years
Groundwater sampling every five years
Noting the presence of lead in the soil on planning maps and GIS systems used in making land use decision in the future and,
Efforts to inform the public and particularly the Colyer Manor residents.
As you all well know, because you live it, Army families move every few years. Some of you may not live here when we start building the fence next summer.
We plan to use the post newspaper, web page, social media, and other resources to make new residents of Colyer Manor aware of the risk and the importance of avoiding exposure to the fenced off area. There are two potential options that are being considered as locations for the fence
The first option would encircle the area of highest lead contamination. This prevents access to all areas where lead levels exceed KDHE standards.
Pros are that it limits the area excluded from other uses, it limits access from the north and overall limits access better than option 2
Cons are that construction and maintenance will be more challenging due to the slope The second option would essentially block easy access to the hillside from the entire housing area by blocking the base of the hill from west to east
This option would be easier to construct since it would be on flatter ground
Cons are that it would likely be more expensive than the estimate, and it doesn’t limit access from the north The next steps in the process are to receive and consider public input, which we are doing with this meeting and accepting during the public review period that runs through Christmas Eve.
After considering any public input and making a decision on the fence location and sign verbiage, the Decision Document would be finalized
Work on the fence could commence in the summer of 2015 I’ll try to answer any questions that I can, and I have my staff, our Corps of Engineers partners, and contractors who are preparing the written plan here –the technical experts –to help me as needed, and our partners from KDHE and the EPA.
Record of Decision Sherman Heights Small Arms Range Impact Slope Fort Riley, Kansas
Attachment 4
Responses to Comments
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TECHNICAL REVIEW COMMENTS Draft Record of Decision for Sherman Heights Small Arms Range Impact Slope Munitions Site Fort Riley, KS February 2015
Name: Amer Safadi, Remedial Project Manager Phone Number: 913-551-7825
Organization: USEPA Region 7 E-mail Address: [email protected]
Comments:
Item Section Page Comment Response General Comments 1 Please ensure that the Final ROD will present figures at a higher The resolution of the figures will be level of quality than presented in the draft copy. checked and improved as requested. 2 There are some inaccuracies with respect to reference citations in The references were reviewed and updated the text and Section 4.0 References. Please review and correct as requested. accordingly. Specific Comments 3 Section 1.1, last Please revise the document to delete this sentence. It does not The text was deleted as requested. sentence match the section title and it is essentially repeated in the next section. 4 Section 1.2, 2nd Please revise this paragraph to briefly explain the role of the US The U.S. Army Corps of Engineers was paragraph Army Corps of Engineers on this project (particularly relative to the the executing agency providing Army). contractual support and Quality Assurance to the Army. Per the USEPA guidance document, Section 1.2 is to discuss the lead agency (i.e. the Army) and support agencies (i.e. the regulators). 5 Section 1.5.1, 1-2 The text states that the selected remedy “utilizes permanent The text was deleted as requested. Part 1 solutions and alternative treatment technology to the maximum extent possible.” The selected remedy does not use “alternative treatment technology” so please remove this text from the document. 6 Section 1.5.2, 2nd Please review this sentence. “Excavation of soils” does not qualify The text was revised as follows: “Removal sentence as a “treatment.” Instead, the steep slopes present would in fact of lead in soil was not recommended due to make excavation of soils difficult, meaning that soil “removals” were the steep slopes present, making
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Item Section Page Comment Response not deemed to be feasible, not soil ''treatment”. It does not appear excavation of soils difficult. Treatment that this section presents the reason(s) why soil treatment was not technologies for lead are not commercially recommended. Please revise the text as appropriate. available.” 7 Section 2.0, 4th Please add the USEPA guidance EPA/540-R-98-031 to the list in The text in Section 2.0 and in the paragraph, 1st Section 4.0 References. Also add the citation of “USEPA, 1999” to references was revised as requested. sentence the text, following the discussion of this guidance document. In this same sentence, (USEPA, 2011) is also cited. This reference does not match what is listed in Section 4.0 References. 8 Section 2.2, 4th 2-3 Please revise the text to include a description of “items” removed The text was revised as requested. paragraph, 5th from the surface and subsurface soils. sentence 9 Section 2.5.6 Please review this section to determine if a reference citation References to the SI report were added to should be included as a source of this information. Sections 2.5.6 and 2.5.7. 10 Section 2.5.7 Please review this section to determine if a reference citation References to the SI report were added to should be included as a source of this information. Sections 2.5.6 and 2.5.7. 11 Section 2.5.8, 1st 2-12 Please replace “studies” with “investigations”. The text was revised as requested. paragraph, 1st sentence 12 Section 2.7.1.1, 9th Please insert “arsenic” prior to “was excluded as a COPC”. The text was revised as requested. sentence 13 Section 2.7.1.4, 2-18 Please revise the text to insert “an unacceptable level of” prior to The text was revised as follows: “Lead first full sentence “risk”. concentrations exceeding the residential and commercial/industrial RSLs were considered to represent a potential unacceptable level of health risk to residents, Post personnel and contractors.” 14 Section 2.7.1.4, 1st 2-18 Please revise the text to insert “an unacceptable level of” prior to The text was revised as follows: full paragraph, last “risk”. “Accordingly, lead within SHSAR Impact sentence Slope was found to represent a potential unacceptable level of health risk to a hypothetical future residential receptor.” 15 Section 2.7.1.4, 2-18 Please verify the accuracy of the ''USEPA, 2010a” reference The reference has been corrected to 2nd full paragraph, citation. It is not correct, compared to the Section 4.0 Reference USEPA, 2011b. In addition, the reference 2nd sentence list. to USEPA, 2011 has been changed to USEPA, 2011a. 16 Section 2.7.1.5, 2-18 For the last two sentences of this bullet, if correct, please revise the The text was revised as follows: “Therefore, fourth bullet text to insert “an unacceptable level of” prior to “risk”. lead in these areas is the primary source of this unacceptable level of risks to human
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Item Section Page Comment Response health.” 17 Section 2.7.2.3 2-20 Please verify if “INRMP, 2010” is a citation for a reference that INRMP, 2010 has been added to Section should be added to Section 4.0 References. 4.0 References as follows: “Fort Riley, 2010. Integrated Natural Resources Management Plan (INRMP). Envrionmental Division, Directorate of Public Works. April 13, 2010.”
In addition, “INRMP, 2010” has been revised to “Fort Riley, 2010”. 18 Section 2.7.2.5, 4th These two bullets appear to contradict each other. One claiming The text was revised as follows: th and 5 bullets potential adverse impacts to populations and the other saying • “Lead is the only contaminant of effects are not expected. Please revise for clarity. Additionally, the concern in soil. While there is phrase “Wildlife population effects” should be clarified. Are these potential for adverse impacts from effects “adverse effects”? lead on populations of ground- dwelling, insectivorous small mammals and birds, and herbivorous birds, adverse impacts on ecological receptors are expected to be overstated due to the conservative nature of the SLERA. “ • “Wildlife population adverse effects are not expected at the residential RSL of 400 mg/kg of lead.” 19 Section 2.9.2, 2-25 Where is the detailed sampling plan for soil and groundwater A LUC Implementation Plan will be Long-Term sampling? Explain. prepared after the ROD is signed. The Monitoring/ following text was added to the end of the Maintenance Long-Term Monitoring/Maintenance paragraph discussion in Section 2.9.2 to clarify: “A LUC Implementation Plan will be drafted following completion of the ROD that will detail the specific sampling locations and frequencies.” 20 Table 2-9 2-27 Overall. protectiveness and Compliance with ARARs are threshold Table 2-9 (Table 2-10 in the revised criteria, which makes them either pass or fail, no intermediate document) was revised as requested. ranking. The degree by which the criterion pass or fails is irrelevant and a ranking like “high” or “moderate” or “low” is inappropriate.
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Item Section Page Comment Response Revise the table to just show that these criteria have either been met or have not been met. 21 Table 2-10 2-28 The note at the bottom of the table, “The USEPA Residential RSLs, Table 2-10 (Table 2-11 in the revised or the KDHE Tier 2 RBCs if they are more conservative, were document) was revised as requested. selected as the (RG) for the SHSAR Impact Slope MRS,” does not make sense at this stage of the project or for this table. Please remove this note and superscript and revise the table to include the USEPA Residential RSL of 400 mg/kg for lead as a TBC criterion. 22 Section 2.10.4 2-29 As noted in this section, “Reduction of toxicity, mobility or volume The second paragraph in Section 2.10.4 through treatment refers to the anticipated performance of the was revised as follows: “No treatment of treatment technologies that may be included as part of a remedy.” lead contaminated soils was evaluated. Thus, as none of the alternatives include treatment to reduce the Therefore, no reduction in toxicity, mobility toxicity, mobility, or volume of contamination at the site, none of or volume through treatment is provided. them meet this criterion. Therefore, please revise this section and However, the monitoring performed under Table 2-9 accordingly. Alternative 2 would ensure that migration of lead from the MRS was not occurring, and additional action may be taken if it is identified. Alternative 3 would effectively reduce mobility of lead-contaminated material by sequestration in a permitted RCRA Subtitle C landfill. The toxicity and volume of the waste would remain the same for material removed from the MRS; however, the risk of exposure to lead- contaminated soil with concentrations exceeding the RG would be eliminated. Alternative 4 does not reduce toxicity or volume of contaminants, since the contaminants would remain at the MRS; however, the mobility of the contaminants would be reduced by the cover.”
Table 2-9 (Table 2-10 in the revised document) was revised to give a rating of “low” for Alternative 2 and following footnote was added to the table: “No treatment is performed in any of the four alternatives. Therefore, no reduction in
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Item Section Page Comment Response toxicity or volume is provided. However, a reduction in mobility is provided by Alternatives 3 and 4, so they were scored “moderate”.” 23 Table 2-11 2-33 Why is the base year listed as 2013? The cost estimate was completed in 2013 for the FS. No changes to the cost estimate have been made for the ROD. 24 Sections 2.10.10- The conclusions presented regarding greenhouse gas emission, No data is available to quantify these 2.10.12 toxic chemical usage and disposal, and energy consumption are discussions which were included in the FS reasonable but appear to be strictly qualitative and not be based on report. No changes to the text were made. any actual calculations. Is there any data evaluation that can be added to help quantitatively bolster the recommendations articulated? 25 Acronyms Please add the following acronyms to the Acronym and The acronym list was updated as Abbreviations list: OHM, MDAS, and INRMP. requested. 26 Section 2.7.1.2, 3rd 2-16 The sentence appears to be incomplete-please revise. The text has been revised as follows: “The paragraph, 2nd 95% UCL is generally used in CERCLA risk sentence assessments to represent a reasonable maximum estimate of the concentration a receptor is likely to be exposed to over time.” 27 Section 2.7.1.2, 3rd 2-16 If correct, please insert “a” after “2010”. The text has been revised to “2010a”. paragraph, 3rd sentence 28 Section 2.7.2.4, This sentence is missing “for” after the phrase “the NOAEL-based The text has been revised as follows: Lead Risk HQs exceed one.” “At the 95% UCL XRF concentration, the Evaluation section, th NOAEL-based HQs exceed one for all 7 sentence receptor groups.” 29 Table 2-8, 2-24 “Excavation of 4,436.7” is missing unit label (cubic yards). Table 2-8 (Table 2-9 in the revised Alternative 3 document) was revised as requested. 30 Section 2.9.3, last 2-25 Please change “remove” should be “removal.” The text was revised as requested. sentence 31 Section 2.10.1, 2nd 2-28 This sentence is incomplete - please revise. The text was revised as follows: paragraph, 3rd “Alternative 2 further provides protection for sentence authorized personnel entering the MRS by requiring LUCs that notify personnel of the potential hazards and ensure personal
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Item Section Page Comment Response protective equipment (PPE) is utilized during any intrusive work at the MRS.” 32 Section 4.0 Please remove the “a” from “USEPA, 2013a” reference The citation was revised as requested. End of Comments
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TECHNICAL REVIEW COMMENTS Final Record of Decision for Sherman Heights Small Arms Range Impact Slope Munitions Site, Revision 01 Fort Riley, KS August 2015
Name: Mary Peterson, Superfund Directory Phone Number:
Organization: USEPA Region 7 E-mail Address: [email protected]
Comments:
Item Section Page Comment Response General Comments 1 Please incorporate the following: The lead is in the form of The following was added to the end of the inorganic projectiles, principally pistol rounds, that were fired at first bullet in Section 2.7.1.5: “Solubility of targets set against the bluff. Additionally, the soils are bicarbonate lead in groundwater is limited, and the soils that form a covering of lead carbonate on any free metal lead water wells at the site are tested regularly present. The lead carbonate is extremely insoluble with a solubility and no lead is present.” product of E10-13. Solubility of lead in groundwater is limited, and the water wells at the site are tested regularly and no lead is A new bullet was added to Section 2.7.1.5 present. as follows: “The lead is in the form of inorganic projectiles, principally pistol rounds, which were fired at targets set against the bluff. Additionally, the soils are bicarbonate soils that form a covering of lead carbonate on any free metal lead present. The lead carbonate is extremely insoluble with a solubility product of 1x10- 13.”
The following was added to the first paragraph in Section 2.9.2: “This is not anticipated at this MRS as the lead is in the form of inorganic projectiles, principally pistol rounds, which were fired at targets set against the bluff. Additionally, the soils are bicarbonate soils that form a covering
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Item Section Page Comment Response of lead carbonate on any free metal lead present. The lead carbonate is extremely insoluble with a solubility product of 1x10-13. Solubility of lead in groundwater is limited, and the water wells at the site are tested regularly and no lead is present.”
Lastly, the first two sentences in the second paragraph in Section 2.10.1 were revised as follows: “Lead is limited to the MRS boundary and migration of lead from the MRS is not anticipated as the lead is in the form of inorganic projectiles, principally pistol rounds, which were fired at targets set against the bluff. Additionally, the soils are bicarbonate soils that form a covering of lead carbonate on any free metal lead present. The lead carbonate is extremely insoluble with a solubility product of 1x10-13. Solubility of lead in groundwater is limited, and the water wells at the site are tested regularly and no lead is present. Alternative 1 provides no effect on the MRS; therefore, it does not address any of the identified risks to human health and the environment. Alternative 2 provides protection to the general public by limiting access to the MRS to which the elevated lead concentrations are limited.” 2 Please incorporate the following: There is a ditch and berm area The following was added to the first between the quarters & the slope base. The Sherman Heights area paragraph in Section 2.9.2: “In addition, is a permanently grass-covered slope, which will alleviate the there is a ditch and berm area between the potential for soil to move downward toward the quarters. housing quarters and the slope base which provide a physical barrier to prevent soil from migrating down the slope. Further, the Sherman Heights area is a permanently grass-covered slope, which will alleviate the potential for soil to move downward toward
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Item Section Page Comment Response the housing quarters.”
In addition, the fifth sentence in the second paragraph in Section 2.10.3 was revised as follows: “Further, there is a ditch and berm area between the housing quarters and the slope base. The Sherman Heights area is a permanently grass-covered slope, which will alleviate the potential for soil to move downward toward the housing quarters. For Alternatives 3 and 4, erosion control may prove to be difficult due to the slopes present.” 3 Please incorporate the following: The slope on which the material is The third sentence in Section 2.9.3 was present is ~30 degrees. The soils are shallow & underlain by lower revised as follows: “It is noted that the slope permeability bedrock. The excavation of contaminated soils would on which the material is present is have a very strong potential to destabilize the slope & cause slope approximately 30 degrees (i.e., a steep failure with a landslide as a result. slope). The soils are shallow and underlain by lower permeability bedrock. The excavation of contaminated soils would have a very strong potential to destabilize the slope and cause slope failure with a landslide as a result.”
In addition, the third paragraph in Section 2.10.6 was revised as follows: “Alternative 3 uses proven, tested technologies that are technically feasible from an engineering perspective. Soil wetting and dust control would be required to protect workers and nearby residents. Noise and traffic disruption impacts on nearby residents during daylight hours will increase during the remedial action but can be mitigated with proactive planning actions. However, there would be design challenges implementing the action due to the slope present and as the soils are shallow and
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Item Section Page Comment Response underlain by lower permeability bedrock. Per Occupational Safety and Health Administration (OSHA) 1926 Subpart P, Excavations, the sandy soil and steep sloping (greater than 1.5:1) may require shoring, or other engineering controls, to provide slope stability during the implementation of the remedial action. The slope of the SHSAR Impact Slope MRS will cause excavation to proceed slower than excavation on less steep slopes and may require specialized equipment, particularly in areas of shallow bedrock; however, the work can still be implemented. Engineering analysis in areas, in particular those areas without shallow bedrock, is required to assess the potential for localized slope failure. The excavation of contaminated soils would have a very strong potential to destabilize the slope and cause slope failure with a landslide as a result. Re- vegetation, erosion control, stabilization, and/or engineering controls may be required in these areas to address slope failure potential if it exists.” 4 Please incorporate the following: A 6' chain link fence with a gate As the design of the fence has not been will be installed around the site. [I am not sure if this action is what developed or approved to date, no she might consider something that will ensure a necessary degree changes to the alternative description of protectiveness. No matter the height of the fence, it will only were made. The response to Comment 1 serve as a challenge to be overtopped short of being electrified in Section 3.1 was revised as follows: with razor wire.] “Fort Riley, the USEPA, and KDHE have not discussed the specific design or location of the fence. That determination is part of the Remedial Design. The Army will strive to not have the fence negatively impact the view. Input will be gathered from the USEPA and KDHE and the final design of the fence will be approved by
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Item Section Page Comment Response the USEPA.”
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TECHNICAL REVIEW COMMENTS Draft Final Record of Decision, Fort Riley, Sherman Heights Small Arms Range Impact Slope Munitions Response Site, Junction City March 2015
Name: Travis Daneke Phone Number: (785) 296-6378
Organization: Kansas Department of Health and Environment/ Email Address: Bureau of Environmental Remediation (KDHE/BER)
Comments:
Item Section Page Comment Response Specific Comments 1 Table 2-9 2-27 This table indicates that Alternatives-1 would have a high The short-term effectiveness, as defined short-term effectiveness. According to Section 2.1 0.5, the no- in the FS and the first paragraph of action of Alternative-1 does not provide any short-term benefit Section 2.10.5, addresses the period of to the site. Please indicate that Alternative #1 has a low short- time needed to implement the remedy term effectiveness. and any adverse impacts that may be posed to workers, the community, and the environment during construction and operation of the remedy until cleanup levels are achieved.
As no actions are implemented under Alternative 1, no short term impacts will occur. In addition, the No Action alternative could be immediately implemented. As such, it has a high short-term effectiveness. It is agreed that it has no benefits. This is evaluated under the long-term effectiveness and permanence criterion. 2 Table 2-9 2-27 Furthermore, this table also indicates that Alternatives-3 Table 2-9 was revised to indicate that would have only a moderate impact on the reduction of Alternative 3 has a high impact on the toxicity, mobility, or volume through treatment. Yet it is states reduction in toxicity, mobility, or volume in Section 2.1 0.4 that Alternative-3 would be effective at as requested. reducing the toxicity, mobility, and volume. Please update
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Item Section Page Comment Response Table 2-9 to indicate that Alternative-3 will have a high impact on the reduction of toxicity, mobility, and volume at this site. End of Comments None required.
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